A fungal growth model fitted to carbon-limited dynamics of Rhizoctonia solani.

Here, a quasi-steady-state approximation was used to simplify a mathematical model for fungal growth in carbon-limiting systems, and this was fitted to growth dynamics of the soil-borne plant pathogen and saprotroph Rhizoctonia solani. The model identified a criterion for invasion into carbon-limited environments with two characteristics driving fungal growth, namely the carbon decomposition rate and a measure of carbon use efficiency. The dynamics of fungal spread through a population of sites with either low (0.0074 mg) or high (0.016 mg) carbon content were well described by the simplified model with faster colonization for the carbon-rich environment. Rhizoctonia solani responded to a lower carbon availability by increasing the carbon use efficiency and the carbon decomposition rate following colonization. The results are discussed in relation to fungal invasion thresholds in terms of carbon nutrition.

The majority of Fc gamma RIII-positive gamma delta T cells do not express HLA-DR in patients with primary Sjögren's syndrome.

The percentages of circulating gamma delta T cells and the proportions of these expressing Fc gamma RIII (CD16) or HLA-DR in patients with primary Sjögren's syndrome (pSS) and controls were determined using monoclonal antibodies and flow cytometry. There was no significant difference in the percentages of gamma delta T cells in the pSS patients compared with controls. There was, however, a significant increase in the proportions of both CD16+ and HLA-DR+ gamma delta T cells in pSS patients. A 3-colour immunofluorescence technique demonstrated that these two markers were mutually exclusive and therefore may identify either subpopulations of gamma delta T cells or different stages of the activation process.

Cell-free CD5 in patients with rheumatic diseases.

Since an increased frequency of CD5+ B cells has been reported in rheumatoid arthritis (RA) and primary Sjögren's syndrome (SS), and the expression of the molecule was reduced on the T cells of some SS patients, we hypothesised that there would be an accelerated turnover of CD5 in these disorders. We describe a novel enzyme-linked immunosorbent assay for measuring cell-free (CF) CD5, using rabbit F(ab')2 anti-CD5 antibody as capture agent and monoclonal anti-CD5 antibody as revealing agent. It was established that CF-CD5 was detectable in RA and SS sera, as opposed to sera from patients with ankylosing spondylitis and normal controls. The level of CF-CD5 did not correlate with rheumatoid factor in RA patients but was significantly higher (P less than 0.05) in SS patients with extraglandular manifestations than in those with glandular disease. Three of the latter patients with significantly increased levels of CD5-negative T cells did not have a particularly high proportion of CF-CD5 in these sera.

CD5+ B cells and the immune system.

The CD5+ B-cell population is prominent in early life and may play a key role in the ontogeny of the immune system. Transplantation studies in mice are in support of CD5+ B cells as a separate lineage from CD5- B cells. In both mice and men there is evidence in favour of CD5 being an activation antigen rather than a lineage marker, but the jury is still out! The frequency of CD5+ B cells appears to be under genetic influence. CD5+ B cells are receptive to many cytokines including IL-2 and IL-5 and themselves produce a number of cytokines especially IL-10. The function of the CD5 molecule on B cells is presently unknown but it might be involved in interaction with CD72 on other B cells. CD5+ B cells generally utilise minimally mutated germ-line genes and produce low avidity auto- and polyreactive antibodies (natural antibodies) generally of the IgM class.

Anti-Epstein-Barr virus-nuclear antigen-1, -2A and -2B antibodies in rheumatoid arthritis patients and their relatives.

We have examined serum antibodies to Epstein-Barr virus Nuclear Antigen (EBNA)-1, -2A and -2B, in addition to antibodies to viral capsid antigen and early antigen in 100 rheumatoid arthritis patients and 50 of their relatives. Using indirect immunofluorescence on transfected cells and Western-blot technique, we have found increased frequency and titres of antibodies to EBNA-2B in patients and, to a lesser degree, in their family members, whereas other anti-Epstein-Barr virus antibodies appeared to be similar to controls. Cross-inhibition experiments were carried out and show that antibodies to EBNA-2A are distinct from those to -2B, and vice versa.

Impaired binding capacity of asialyl and agalactosyl IgG to Fc gamma receptors.

OBJECTIVE: Autoimmunity in rheumatoid arthritis has been associated with deficient glycosylation of serum and synovial IgG which could potentially be mediated through the binding of the Fc portion of the molecule to its cognate receptor. METHODS: Normal IgG1 and IgG3 were affinity-purified, and sialic acid and galactose were clipped off using neuraminidase and beta-galactosidase, respectively. The binding of these sugar-depleted IgG to the Fc gamma receptors (Fc gamma R)IIIb on polymorphonuclear leukocytes (PMN) was assessed by flow cytometry. RESULTS: The binding of both asialyl and agactosyl IgG1 and IgG3 to PMN was significantly lower than that of the native IgG1 and IgG3. CONCLUSION: These data indicate that agalactosyl and, to a lesser degree, asialyl IgG, do not bind as efficiently as native IgG to Fc gamma R. Such a reduction in the perspective of the heterogeneity of the PMN Fc gamma RIIIb.

Tiopronine-induced reduction of rheumatoid factor functional affinity and asialylated IgG in patients with rheumatoid arthritis.

Serum and synovial fluid (SF) from 16 rheumatoid arthritis patients were evaluated before and after a 2-month treatment with tiopronine (TP). The levels of rheumatoid factor (RF) declined, as did the functional affinity of the remaining RF (p less than 0.01 in serum and p less than 0.05 in SF). Concomitant restoration of the sialylation of IgG was observed (p less than 0.05 in serum and SF). Following an initial increase, a significant reduction was observed in the level of soluble interleukin-2 receptors in serum (p less than 0.05) and SF (p less than 0.05) after treatment with TP.

[The association of lung cancer and atheromatous arterial disease]. / Etude de l'association cancer broncho-pulmonaire et arthériopathie athéromateuse.

This work is based on the retrospective study of the case history of 26 patients who were treated between September 1979 and January 1987 in the department of thoracic and vascular surgery at the Avicenne Hospital--and who were all suffering from both lung cancer and atheromatous arterial disease. It is now well established by all the epidemiologic research that the link between lung cancer and atheromatous arterial disease is smoking tobacco. The risks involved in the misunderstanding of such an association are not without danger for the patient, particularly the risk of severe complication of possible coronary or carotid lesions, threatening survival; from this derives the necessity to decide automatically for a minimum of pre-surgery vascular investigations in the case of patients suffering from lung cancer. The therapeutic strategy in this association must be thorough, considering that there are three priorities in the vascular field which must absolutely be treated before the lung itself: --the coronary and carotid lesions which are likely to be complicated cancer after surgery and any state of emergency in the other vascular territories. The fight against tobacco smoking must also be considered as a priority aim.

[Thoracic wounds. Therapeutic approach. Apropos of 77 cases]. / Plaies thoraciques. Attitudes thérapeutiques. A propos de 77 cas.

We have led over a four year period, from 1981 to 1985, a prospective study on all cases of penetrating chest wounds (77 cases) in the intensive Care unit and the Department of Thoracic Surgery at the Avicenne Hospital. These wounds, involving young males, are fortunately mostly benign. Their seriousness is based on the abdominal or mediastinal hemorrhage as well as lesions to the vital organs which need an emergency intervention. The latter, nevertheless, with the help of the mobile reanimation service for transfering the patient, has diminished the mortality rate to 2.6 per cent. Following their experiment and after a review of the literature, the authors expose their method of management of the penetrating chest wounds.

[Pericardioscopy: definition, value and limitation]. / La péricardoscopie: définition, intérêt et limite.

After thoracoscopy and mediastinoscopy, pericardioscopy now completes the endoscopic techniques available for exploration of the pericardial cavity. During one year, we systematically associated pericardioscopy with pericardial drainage, using a mediastinoscope. Pericardioscopy visualizes the pericardium and guides biopsies. We report here this one-year experience of 12 pericardioscopies, describing the technique and listing its indications.

[Thoracic splenosis]. / Splénose thoracique.

Thoracic splenosis is the autotransplantation of splenic tissue in the thorax after an injury of the spleen with a tear of the hemi-diaphragm. Usually, there is no symptom and it is unfrequent. A scintigraphy with 99 m. Tc. sulfur colloid and a scan with 99 m. Tc. tagged-heated red cells give the diagnosis. For now, it is no necessary to operate these patients to remove these thoracic nodules.

[Infectious origin of rheumatoid arthritis]. / Origine infectieuse de la polyarthrite rhumatoïde.

Three preliminary concepts are developed: antigen presentation, "peptidic self" and superantigen. Several infectious contenders for rheumatoid arthritis (RA) are then reviewed: Epstein-Barr virus, mycobacteria, parvovirus, proteus and streptococcus. Finally, the most important hypotheses are discussed: microbe present and still accessible, microbe present but hidden, microbe absent but perpetuated by the immune system. In the latest case, molecular mimicry could possibly be the mechanism operating in RA.

The popliteal entrapment syndrome.

Five examples of the popliteal entrapment syndrome have been reported in 4 patients aged between 17 and 41. The diagnosis in each case was made pre-operatively. The anatomical anomalies consisted in three instances of an abnormally high insertion of the inner gemellus (medial head of gastrocnemius) muscle tendon with the artery located twice in front and once in the middle of the tendon, in another instance compression was due to a hypertrophic musculus plantaris and finally, in the last instance, the anomalies were caused by abnormal fibrous bands. In two instances the artery was thrombosed, in three it was compressed in an intermittent fashion. The patients responded well to treatment, by a graft in the case of thrombosis, and by sectioning the abnormal insertions of the gemellus muscle or the fibrous bands in the others. The frequency of these different anatomical types, the relative evolutivity and the embryological hypotheses are studied in the 111 cases recorded in the literature between 1970 and 1983.