Search PubMed⌕ Search

Biomedical subjects

F Bernard

Publications and source records attributed to F Bernard.

At least 91 records · Page 5Linked to original sources
PubMed1992

Protection against Chlamydia psittaci in mice conferred by Lyt-2+ T cells.

A murine model was used to study the respective roles of L3T4+ and Lyt-2+ T cells in protection against Chlamydia psittaci. Donor mice were intravenously (i.v.) infected with 1 x 10(5) plaque-forming units (PFU) per mice of live C. psittaci. One month after inoculation, splenic cells from donors were transferred into syngenic recipients (5 x 10(7) cells/mouse). As measured by splenic colonization on Day 6 after i.v. challenge (1 x 10(5) PFU/mouse), transfer with primed (untreated) cells conferred a 3 log protection in this model. In vitro treatment, before transfer, of splenic cells with anti-Lyt-2 monoclonal antibody (mAb) and complement, markedly impaired the protection in comparison with control mice transferred with primed untreated cells, whereas treatment with anti-L3T4 mAb did not reduce the transferred protection. Resistance to a reinfection with C. psittaci was also studied after selective in vivo depletion of L3T4+ and Lyt-2+ T cells. One month after primary infection, mice were treated with anti-L3T4 or anti-Lyt-2 mAb and challenged thereafter (i.v., 1 x 10(5) PFU). The splenic colonization on Day 6 after challenge demonstrated that treatment with anti-Lyt-2 mAb impaired resistance against a subsequent infection with C. psittaci. Treatment with anti-L3T4 mAb in vivo had no effect on protection, as previously described in vitro. The mechanisms by which Lyt-2+ T cells could participate in the elimination of bacteria were discussed.

Animals↗
PubMed1992

[Neuroblastoma, factor of early decompensation of tetralogy of Fallot].

The authors report the case of a tetralogy of Fallot associated with a neuroblastoma secreting large quantities of noradrenaline. Anoxic decompensation of the tetralogy of Fallot occurred early at the age of 4 months with cyanotic crises associated with an impression of abdominal pain. A systemic-pulmonary anastomosis was performed and the cyanosis regressed but the crises persisted and investigations showed the presence of a neuroblastoma. The tumour was treated by surgery and chemotherapy and has not recurred after 2 years' follow-up. Complete repair of the tetralogy of Fallot was performed secondarily at the age of 2. In this case, the high concentration of circulating catecholamines was probably a factor of early decompensation of the tetralogy of Fallot by infundibular spasm. A review of the literature revealed 26 cases of cardiac disease with a peripheral neurogenic tumour. Two pathogenic mechanisms are suggested: an embryological abnormality of cardiac cell migration from the neural crest and chronic stimulation of neuroblastic cells by chronic hypoxia.

Humans↗
PubMed1991

[Acute intestinal ischemia after voluntary drug poisoning].

A case is reported of a patient who suffered from ischaemic enteritis after having taken an overdose of several drugs. The 42-year-old woman was found out no more than 7 h after she had taken a mixture of benzodiazepines, tricyclic antidepressants and barbiturates (4 mg.l-1 blood level on admission). She had been lying against a bedpost, resulting in compression of her anterior abdominal wall below the umbilicus, involving her right femoral nerve. There was a severe rhabdomyolysis. Despite clinical improvement, the patient being extubated the following day, her abdomen remained painful and swollen. A CT abdominal scan showed a peritoneal effusion and a distended small bowel. Laparatomy revealed severe ischaemia of the terminal 80 cm of ileum, with some gangrenous areas. This was resected, and a right-sided ileostomy performed. Histopathological examination demonstrated a mucosal necrosis without mesenteric arterial thrombosis. A bilateral pleural effusion occurred during postoperative course, requiring drainage. Thereafter, the clinical course was uneventful, with intestinal continuity being re-established three months later. The femoral paralysis receded spontaneously. It is likely that this unusual postural complication of coma may be attributed to a transient compression of mesenteric vessels.

Acute Disease↗
PubMed1991

Study of the vasodilating activity of salbutamol on dog coronary arteries. Unexpected effects of methylene blue.

The vascular relaxant effect of salbutamol and its dependence on the endothelium were studied in the isolated dog coronary artery, precontracted with prostaglandin F2 alpha. Salbutamol induced a concentration-dependent relaxation which was partially inhibited by removal of endothelial cells. Atenolol 10(-6) mol/l, a beta 1-selective antagonist, inhibited the relaxant effect of salbutamol both in the presence and in the absence of endothelium. Conversely, ICI 118,551 10(-6) mol/l, a beta 2-selective antagonist, antagonized the response to salbutamol only in intact vessels. Methylene blue amplified markedly the relaxation to salbutamol but only in denuded rings. Therefore, the vasodilating effect of salbutamol on large coronary arteries seems to result from the stimulation of both, beta 1-receptors on smooth muscle cells and beta 2-receptors on endothelial cells, demonstrating the existence of the two types of adrenoceptors in the wall of large dog coronary arteries. In addition, the effect obtained with methylene blue in this study shed some doubts on its specificity as a guanylate cyclase inhibitor.

Adrenergic beta-Antagonists↗
PubMed1991

Phenotypic analysis of splenic lymphocytes and immunohistochemical study of hepatic granulomas after a murine infection with Salmonella abortusovis.

Infection in mice with an attenuated strain of Salmonella abortusovis (SAO), a specific pathogen for sheep, was used as a convenient model to understand further the induced immunity against SAO. The hypovirulent Rv6 strain, subcutaneously inoculated in salmonella-susceptible BALB/cby (Itys) mice, colonized the spleen and the liver in less than 6 days post-infection (PI) to be cleared after Day 28 PI. Simultaneously, an increase in spleen cell numbers, splenomegaly and hepatic granulomatous lesions developed to a maximum level on Day 9 PI. In spleen of uninfected mice, the number of Thy-1.2+ cells represents twice the number of surface immunoglobulin-positive cells (sIg+). Cytofluorometric analysis of the spleen lymphoid cell subsets showed a significant increase (10 times, P less than 0.05) in the number of sIg+ cells from Day 6 to Day 28 PI compared to control values. The number of Thy-1.2+ cells also significantly increased, to a lesser degree than the sIg+ cells, on Day 2 and on Day 16 PI (twice control values, P less than 0.05), but decreased on Day 6 PI compared to Day 2 PI. The highest L3T4+:Lyt-2+ ratio was observed on Day 2 PI and the lowest on Day 9 PI. On Day 28 PI, the number of sIg+ cells was still greater than the number of Thy-1.2+ cells. The granulomatous lesions were observed in the liver as early as Day 2 PI and their frequency was maximal on Day 9 PI. Immunohistochemical analysis of the granulomatous lesions showed that macrophages (F4/80+, Mac1+) were the basic cells and that L3T4+ cells were the predominant T cells. In well-developed granulomas observed on Day 9 PI, macrophages were in the centre whereas L3T4+ T cells were preferentially located at the periphery. T cells expressing Lyt-2 antigen were rarely detected. Variations in the proportion of lymphoid cells in the spleen and in hepatic granulomatous lesions suggest different and complementary effector mechanisms in induced immunity against SAO.

Animals↗
PubMed1991

Magnetic resonance imaging in gangliogliomas and gangliocytomas of the nervous system.

Gangliogliomas and gangliocytomas are rare and benign neuronal tumors which affect young subjects. This study concerns 3 cases of ganglioglioma and 3 cases of gangliocytoma explored by CT and MRI and confirmed by pathological examination. The most typical CT image was that of an often calcified contrast-enhanced cystic tumor. At MRI, each tumor emitted a low-intensity signal on T1-weighted sequences and a high-intensity signal on T2-weighted sequences. Contrast enhancement after gadolinium injection was frequent. Neuroradiology is not specific, and these tumors are usually diagnosed at pathology. However, the diagnosis may be considered in young patients with a history of old, drug-resistant partial epilepsy and having a contrast-enhanced, calcified cystic lesion in the temporal lobe or the cerebellum.

Adolescent↗
PubMed1990

Two cases of severe infection with beta-haemolytic group A streptococci associated with a toxic-shock-like syndrome.

Two cases of severe infection due to Streptococcus pyogenes associated with a toxic-shock-like syndrome (TSLS) and also with serious soft-tissue infection are described. Serotyping and detection of A, B and C exotoxins were carried out on strains isolated from blood cultures and skin samples. The strain of serotype M1 T1, which produced 10 ng/ml of exotoxin A and also synthesised exotoxins B and C, caused severe TSLS associated with major skin lesions. The second strain of serotype M12 T12, which produced only 1 ng/ml of exotoxin A and synthesised exotoxin B, was associated with clinical manifestations of adult respiratory distress syndrome. The relationship between the magnitude of exotoxin production and the severity of clinical manifestations cannot be established from these two cases.

Adult↗
PubMed1990

Protective effect of polyclonal and monoclonal antibodies against abortion in mice infected by Chlamydia psittaci.

The role of antibody in preventing placental and fetal infection by Chlamydia psittaci was studied in mice. Pregnant mice were passively immunized with polyclonal sera or monoclonal antibodies (mAbs) at day 11 of gestation. The mice were intravenously challenged the following day with the virulent AB7 ovine abortion strain of C. psittaci. Mice were either killed on day 16 of gestation to determine placental and fetal chlamydial infection levels or were permitted to have and raise their young until 8 days old for comparison of survival rates. Immune sera produced a decrease in both placental and fetal infection and reduced the number of young dying in utero or shortly after birth. Polyclonal sera to the highly invasive AB7 and AB4 strains or to the invasive 1B strain were more effective than serum to the invasive AB13 strain. The B577/F3 and B577/A11 monoclonal antibodies gave almost complete protection, with only low levels of placental infection and no detectable fetal infection or decrease in survival rate. The study demonstrates that immune sera and type-specific mAbs can passively transfer resistance to placental and fetal colonization and to abortion and fetal loss in mice intravenously challenged with P. psittaci.

Abortion, Septic↗