[Pulmonary Metastase of a Knee Mycetoma in Senegal]. / Métastase pulmonaire d'un mycétome du genou au Sénégal.

Mycetoma is transmitted by thorns infected. The commonest site for mycetoma is the foot. The primary pulmonary are rare and usually secondary to other primary site. We report a case of pulmonary fungal mycetoma secondary to primary site in the knee. We do a review of the literature and we discuss the way of dissemination.

Le mycétome se transmet principalement par piqures d'épines d'arbustes infectés. Les localisations primitives au niveau du pied sont les plus fréquentes. Les localisations pulmonaires sont exceptionnelles et secondaires à des localisations périphériques primitives. Nous rapportons un cas de localisation pulmonaire d'un mycétome fongique secondaire à une localisation au niveau du genou, puis nous faisons une revue de la littérature et nous discutons de la voie de dissémination.

[Recidives of Mycetoma after Amputation in Dakar (Senegal)]. / Récidives de mycétome après amputation à Dakar (Sénégal).

The treatment of fungal mycetoma is essentially surgical. This carcinological-like surgery consists of amputation in case of bone involvement. The recurrences after amputation are rare and address the problem of the operative indication. We report 5 cases of recurrence of fungal black-grain mycetoma after amputation of leg or thigh. Case 1: a 52-year-old patient with a mycetoma of the knee evolving for 8 years. There is no history of surgery. A thigh amputation with ganglion dissection is performed. One year after the surgical procedure, the patient presents a recurrence on the amputation stump and on the lymph node dissection site. An indication of hip disarticulation is made and performed 17 months after amputation. Case 2: a 25-year-old patient who has a black-grain mycetoma of the foot with osteitis evolving since 10 years. A leg amputation was performed. The patient had a recurrence at the popliteal level at 15 months postoperatively. An indication of amputation of the thigh is posed and refused by the patient. Case 3: a30-year-old woman with black-grain mycetoma of the knee with bone involvement for more than 10 years. A thigh amputation was performed and at nine months postoperativeshe presented a recurrence in the amputation stump. She was lost of sight despite the decision of surgical revision. Case 4: a 43-year-old patient operated on his foot and leg mycetoma at least 5 timesbefore amputation in 2000. The recurrence occurred one year after amputation. 18 years after amputation, a new surgical procedure was difficult due to extension of the lesions in the pelvis. Case 5: a 50-year-old female patient operated in Mauritania in 2012 (thigh amputation for mycetoma of the knee). She presented a recurrence on the amputation stump in 2018. An indication of disarticulation of the hip was posed and refused by the patient. These recurrences were testified by to the persistence of grains on the preserved segment. They pose the problem of the level of amputation and therefore of preoperative planning. Good preoperative planning allows optimization of the surgical procedure and avoids certain recurrences.

La chirurgie constitue le temps essentiel du traitement des mycétomes fongiques. Elle consiste en une amputation en cas d'atteinte osseuse. Nous avons observé 5 cas de récidives après amputation pour mycétome. Il s'agit dans tous les cas de patients présentant des mycétomes à grain noir avec atteintes osseuses. Les récidives sont survenues à moins de 18 mois de l'amputation faisant parler de reprise évolutive et posant le problème du niveau de l'amputation.

Surgical Treatment of Angular Pott's Kyphosis with Posterior Approach, Pedicular Wedge Osteotomy and Canal Widening.

BACKGROUND: It has been observed that the correction of severe posttuberculous angular kyphosis is still a challenge, mainly because of the neurologic risk. METHODS: Nine patients were reviewed after surgery (mean follow-up 18 months). There were 2 thoracic, 4 thoraco-lumbar and 3 lumbar kyphosis. The mean age at surgery was 23. Clinical results were evaluated by the Oswestry Disability Index (ODI) and by the neurologic evaluation. Preoperative, postoperative and final follow-up X-rays were assessed. The surgery included a posterior approach with cord release and correction by transpedicular wedge osteotomy and widening of the spinal canal. RESULTS: Average kyphotic angulation was 72° before surgery, 10° after surgery and 12° at follow-up. Three out of four patients with neural deficit showed improvement. Neurologic complications included a transitory quadriceps paralysis, likely by foraminal compression of the root. CONCLUSION: A posterior transpedicular wedge osteotomy allows a substantial correction of the kyphosis, more by deflexion than by elongation, with limited neurologic risks. However it is mandatory to widely enlarge the spinal canal on the levels adjacent to the osteotomy, in order to allow the dura to expand backwards.

Modified Dunn osteotomy using an anterior approach used to treat 26 cases of SCFE.

INTRODUCTION: Osteotomy performed below the femoral neck plays a leading role in the treatment of slipped capital femoral epiphysis (SCFE). It results in anatomical reduction. Several modifications have been made to Dunn's original osteotomy technique. We have developed another modification to this technique that uses an anterior surgical approach on a traction table with fluoroscopy control. HYPOTHESES: Will this technique help to reduce the number of complications? Will its results be superior to those achieved with the standard Dunn osteotomy procedure? MATERIAL AND METHODS: This was a retrospective single-center study of 26 cases in 24 patients (2 bilateral cases). Patients were positioned supine on a traction table with fluoroscopy control. An anterior surgical approach was used. A trapezoid-shaped osteotomy was performed below the femoral head. The head's reduction was checked on the fluoroscope and the fixation confirmed. The Postel Merle d'Aubigné (PMA) score was used for the clinical assessment. The radiographic assessment was based on Southwick's angle. RESULTS: The mean slip angle of the femoral head was 57°. A mean correction of 47° was achieved. Based on the PMA score, good and excellent results were achieved in 20 cases (77%) and poor results occurred in 6 cases (23%). The surgical treatment had a significant effect on the PMA score (P=0.0008). In terms of complications, there were five cases of chondrolysis and one case of necrosis associated with chondrolysis. DISCUSSION: The anterior approach provides direct access to the femoral neck, and thereby a cautious osteotomy at the site of the slip itself. Use of a traction table makes the external manipulations, reduction and fixation procedures easier to carry out. The results of this study were comparable to published results. LEVEL OF PROOF: IV, retrospective treatment study.

Hypervirulence of a rough variant of the Mycobacterium abscessus type strain.

We isolated a rough variant of Mycobacterium abscessus CIP 104536T during experimental infection of mice. We show that this variant has lost the ability to produce glycopeptidolipids, is hyperlethal for C57BL/6 mice infected intravenously, and induces a strong tumor necrosis factor-alpha response by murine monocyte-derived macrophages.

Mycobacterium smegmatis laminin-binding glycoprotein shares epitopes with Mycobacterium tuberculosis heparin-binding haemagglutinin.

Mycobacterium tuberculosis, the causative agent of tuberculosis, produces a heparin-binding haemagglutinin adhesin (HBHA), which is involved in its epithelial adherence. To ascertain whether HBHA is also present in fast-growing mycobacteria, Mycobacterium smegmatis was studied using anti-HBHA monoclonal antibodies (mAbs). A cross-reactive protein was detected by immunoblotting of M. smegmatis whole-cell lysates. However, the M. tuberculosis HBHA-encoding gene failed to hybridize with M. smegmatis chromosomal DNA in Southern blot analyses. The M. smegmatis protein recognized by the anti-HBHA mAbs was purified by heparin-Sepharose chromatography, and its amino-terminal sequence was found to be identical to that of the previously described histone-like protein, indicating that M. smegmatis does not produce HBHA. Biochemical analysis of the M. smegmatis histone-like protein shows that it is glycosylated like HBHA. Immunoelectron microscopy demonstrated that the M. smegmatis protein is present on the mycobacterial surface, a cellular localization inconsistent with a histone-like function, but compatible with an adhesin activity. In vitro protein interaction assays showed that this glycoprotein binds to laminin, a major component of basement membranes. Therefore, the protein was called M. smegmatis laminin-binding protein (MS-LBP). MS-LBP does not appear to be involved in adherence in the absence of laminin but is responsible for the laminin-mediated mycobacterial adherence to human pneumocytes and macrophages. Homologous laminin-binding adhesins are also produced by virulent mycobacteria such as M. tuberculosis and Mycobacterium leprae, suggesting that this adherence mechanism may contribute to the pathogenesis of mycobacterial diseases.

What are the immunologically active components of bacille Calmette-Guérin in therapy of superficial bladder cancer?

The subcomponents of bacille Calmette-Guérin (BCG) involved in the mechanism of action of intravesical BCG immunotherapy used for prophylaxis of superficial bladder cancer recurrences have been poorly investigated. We purified various BCG subcomponents and analyzed in vitro their ability to enhance a Th1 polarized immune response as well as to increase lymphocyte-mediated cytotoxicity against bladder tumors. Human peripheral blood mononuclear cells (PBMCs) from healthy purified protein derivative-positive subjects were incubated for 7 days with whole BCG and various fractions (BCG cell wall, plasma membrane, cytosol, purified polysaccharides as glucan or arabinomannan, purified native proteins from BCG culture filtrate, recombinant 22 kDa protein, phosphate transporter PstS-2 and -3 proteins). IFN-gamma, IL-12, IL-2, and IL-6 production by stimulated PBMCs was compared to unstimulated controls and the phenotype of expanded cells analyzed by flow cytometry (FACS analysis). A (51)Cr-release assay monitored the cytotoxicity of amplified effector cells against T24 bladder tumor cells. Live BCG and most of its subcomponents (with the exception of cytosol, PstS-2 and -3) significantly enhanced IFN-gamma and IL-12 secretion, expanded CD3(-)CD56(+) cells and the non-MHC-restricted cytotoxicity against bladder tumor cells compared to unstimulated controls (all P < 0.001, t-test). IL-2 receptor blockage resulted in a clear reduction in the cytotoxic activity of stimulated PBMCs. Numerous BCG subcomponents thus provide positive stimuli for Th1 cell differentiation and enhance in vitro, non-MHC-restricted cytotoxicity against bladder tumor cells. Our findings provide the basis for the therapeutic use of several of these subfractions in experimental animal models bearing bladder tumors.

Inactivation of the antigen 85C gene profoundly affects the mycolate content and alters the permeability of the Mycobacterium tuberculosis cell envelope.

The antigen 85 complex of Mycobacterium tuberculosis consists of three abundantly secreted proteins. The recent characterization of a mycoloyltransferase activity associated in vitro with each of these antigens suggested that they are potentially important for the building of the unusual cell envelope of mycobacteria. To define the physiological role of these proteins, the gene coding for antigen 85C was inactivated by transposon mutagenesis. The resulting mutant was shown to transfer 40% fewer mycolates to the cell wall with no change in the types of mycolates esterifying arabinogalactan or in the composition of non-covalently linked mycolates. As a consequence, the diffusion of the hydrophobic chenodeoxycholate and the hydrophilic glycerol, but not that of isoniazid, was found to be much faster through the cell envelope of the mutant than that of the parent strain. Taken together, these data demonstrate that: (i) antigen 85C is involved directly or indirectly in the transfer of mycolates onto the cell wall of the whole bacterium; (ii) the enzyme is not specific for a given type of mycolate; and (iii) the cell wall-linked mycolate layer may represent a barrier for the diffusion of small hydrophobic and hydrophilic molecules.

The capsule of Mycobacterium tuberculosis and its implications for pathogenicity.

Mycobacterium tuberculosis, one of the most prevalent causes of death worldwide, is a facultative intracellular parasite that invades and persists within the macrophages. Within host cells, the bacterium is surrounded by a capsule which is electron-transparent in EM sections, outside the bacterial wall and plasma membrane. Although conventional processing of samples for microscopy studies failed to demonstrate this structure around in vitro-grown bacilli, the application of new microscopy techniques to mycobacteria allows the visualization of a thick capsule in specimen from axenic cultures of mycobacteria. Gentle mechanical treatment and detergent extraction remove the outermost components of this capsule which consist primarily of polysaccharide and protein, with small amounts of lipid. Being at the interface between the bacterium and host cells, the capsule and its constituents would be expected to be involved in bacterial pathogenicity and past work supports this concept. Recent studies have identified several capsular substances potentially involved in the key steps of pathogenicity. In this respect, some of the capsular glycans have been shown to mediate the adhesion to and the penetration of bacilli into the host's cells; of related interest, secreted and/or surface-exposed enzymes and transporters probably involved in intracellular multiplication have been characterized in short-term culture filtrates of M. tuberculosis. In addition, the presence of inducible proteases and lipases has been shown. The capsule would also represent a passive barrier by impeding the diffusion of macromolecules towards the inner parts of the envelope; furthermore, secreted enzymes potentially involved in the detoxification of reactive oxygen intermediates have been identified, notably catalase/peroxidase and superoxide dismutase, which may participate to the active resistance of the bacterium to the host's microbicidal mechanisms. Finally, toxic lipids and contact-dependent lytic substances, as well as constituents that inhibit both macrophage-priming and lymphoproliferation, have been found in the capsule, thereby explaining part of the immunopathology of tuberculosis.

Fusion of azurophil granules with phagosomes and activation of the tyrosine kinase Hck are specifically inhibited during phagocytosis of mycobacteria by human neutrophils.

Pathogenic mycobacteria parasitize macrophages and reside within phagosomes, which do not fuse with lysosomal granules. Mycobacteria are also internalized by neutrophils, which possess at least two types of granules, specific and azurophil granules, the latter being specialized lysosomes. Here, we investigated the ability of mycobacteria to inhibit the fusion of these granules with their phagosomes in human neutrophils. It was found that when pathogenic (Mycobacterium kansasii and Mycobacterium avium) or nonpathogenic (Mycobacterium smegmatis and Mycobacterium phlei) mycobacteria were internalized by neutrophils, they induced the inhibition of azurophil granule fusion with phagosomes even when they were serum opsonized. In contrast, secretion of specific granule content and production of O2-, both of which contribute to the neutrophil bactericidal response, were triggered. Hck is a Src family tyrosine kinase associated with azurophil granules. During internalization of zymosan, azurophil granules fused with phagosomes and Hck was activated and translocated to the phagosomal membrane, whereas in neutrophils engulfing mycobacteria, Hck did not translocate and remained unactivated. The activation of the tyrosine kinase Fgr was not affected. These results indicate that 1) pathogenic and nonpathogenic mycobacteria trigger similar bactericidal responses in neutrophils, 2) phagocytosis and fusion of azurophil granules can be uncoupled by mycobacteria, and 3) Hck could be one of the key elements of the azurophil secretory pathway that are altered during phagocytosis of mycobacteria.

Interaction of mycobacterial glycolipids with host cells.

Mycobacteria elaborate a great variety of glycolipids of rather exotic structure. Some of these lipids are abundant cell envelope components and are exposed on the bacterial surface. These comprise the species-specific phenolic glycolipids, glycopeptidolipids, sulfatides, and lipooligosaccharides, and the ubiquitous phosphatidylinositolmannosides. Because pathogenic mycobacterial species are facultative intracellular parasites that infect and reside in host cells, some of them may represent potential virulent factors as they have been shown to inhibit both macrophage antimicrobial activities and lymphoproliferation. These biologic activities may derive, at least in part, from the modulation of the cell functions through the interactions between host membranes and these surface-exposed lipids whose structures are different from those of mammalian cell membrane components. In few cases purified glycolipids have been shown to profoundly affect the physical and functional properties of biologic membranes. Therefore, the enzymes involved in the biosynthesis of the biologically active glycolipids represent potential drug targets. However, definite proofs of their implication in the mycobacterial pathogenicity are lacking. Mutants unable to elaborate defined glycolipids are needed.

Predominant structural features of the cell wall arabinogalactan of Mycobacterium tuberculosis as revealed through characterization of oligoglycosyl alditol fragments by gas chromatography/mass spectrometry and by 1H and 13C NMR analyses.

The peptidoglycan-bound arabinogalactan of a virulent strain of Mycobacterium tuberculosis was per-O-methylated, partially hydrolyzed with acid, and the resulting oligosaccharides reduced and O-pentadeute-rioethylated. The per-O-alkylated oligoglycosyl alditol fragments were separated by high pressure liquid chromatography and the structures of 43 of these constituents determined by 1H NMR and gas chromatography/mass spectrometry. The arabinogalactan was shown to consist of a galactan containing alternating 5-linked beta-D-galactofuranosyl (Galf) and 6-linked beta-D-Galf residues. The arabinan chains are attached to C-5 of some of the 6-linked Galf residues. The arabinan is comprised of at least three major structural domains. One is composed of linear 5-linked alpha-D-arabinofuranosyl (Araf) residues; a second consists of branched 3,5-linked alpha-D-Araf units substituted with 5-linked alpha-D-Araf residues at both branched positions. The non-reducing terminal region of the arabinan was characterized by a 3,5-linked alpha-D-Araf residue substituted at both branched positions with the disaccharide beta-D-Araf-(1----2)-alpha-D-Araf. 13C NMR of intact soluble arabinogalactan established the presence of both alpha- and beta-Araf residues in this domain. This non-reducing terminal motif apparently provides the structural basis of the dominant immunogenicity of arabinogalactan within mycobacteria. A rhamnosyl residue occupies the reducing terminus of the galactan core and may link the arabinogalactan to the peptidoglycan. Evidence is also presented for the presence of minor structural features involving terminal mannopyranosyl units. Models for most of the heteropolysaccharide are proposed which should increase our understanding of a molecule responsible for much of the immunogenicity, pathogenicity, and peculiar physical properties of the mycobacterial cell.

Polyphthienoyl trehalose, glycolipids specific for virulent strains of the tubercle bacillus.

Phthienoic acids constitute a family of dextro-rotary odd-numbered unsaturated fatty acids isolated exclusively from virulent strains of human and bovine tubercle bacilli. In the bacterial cell they are not free and a search for their linked form in complex wall lipids of Mycobacterium tuberculosis (strain Canetti) showed that they esterified trehalose. Structural elucidation of the major phthienoyl trehalose showed the occurrence of five acyl residues located at 2, 2', 3', 4 and 6' positions of trehalose. The acyl substituents were mainly 2,4,6-trimethyl tetracos-2-enoic acid (C27 phthienoic acid) accompanied by its homologs. In addition to these branched fatty acids, straight-chain C16 and C18 acyls composed about 20% of the substituents. The proposed structure is a new one, both for the mycobacterial-specific glycolipid and for the substituted positions on trehalose. Other minor acyl trehaloses were detected in M. tuberculosis (strain Canetti), differing from the major component by the occurrence of an additional hydroxy fatty acid (3-hydroxy-2,4,6-trimethyl tetracosanoic acid) or by the number of acyl substituents. The major glycolipid presented a weak activity in vitro on mitochondrial oxidative phosphorylation. These glycolipids and phthienoic acids could serve as virulence indicators.

Induction of polyploid nuclei in the plasmodium of Physarum polycephalum by platinum antitumor compounds.

The intranuclear mitosis of the plasmodial nuclei of myxomycetes permits the observation of defects in chromosomal repartition which would probably be lethal in other eukaryotic cells with open mitosis. We found that antitumoral platinum-amine compounds perturbed late mitotic events and induced the formation of giant nuclei which were polyploid in plasmodia of Physarum polycephalum. Using 26 platinum-amine complexes, we have shown that all antitumoral compounds induced the formation of polyploid nuclei for drug concentrations at least three times lower than the amount necessary to block the overall plasmodial growth, whereas platinum compounds without antitumor activity did not behave this way. DNA replication appeared to be quantitatively normal during formation of giant nuclei by antitumoral compounds. These observations suggest that platinum-amine compounds exert their antitumor activity by interfering with mitosis rather than by a gross inhibition of DNA synthesis.