Unsupervised fuzzy binning of metagenomic sequence fragments on three-dimensional Barnes-Hut t-Stochastic Neighbor Embeddings

Shotgun metagenomic studies attempt to reconstruct population genome sequences from complex microbial communities. In some traditional genome demarcation approaches, high-dimensional sequence data are embedded into two-dimensional spaces and subsequently binned into candidate genomic populations. One such approach uses a combination of the Barnes-Hut approximation and the $t -$Stochastic Neighbor Embedding (BH-SNE) algorithm for dimensionality reduction of DNA sequence data pentamer profiles; and demarcation of groups based on Gaussian mixture models within humanimposed boundaries. We found that genome demarcation from three-dimensional BH-SNE embeddings consistently results in more accurate binnings than 2-D embeddings. We further addressed the lack of a priori population number information by developing an unsupervised binning approach based on the Subtractive and Fuzzy c-means (FCM) clustering algorithms combined with internal clustering validity indices. Lastly, we addressed the subject of shared membership of individual data objects in a mixed community by assigning a degree of membership to individual objects using the FCM algorithm, and discriminated between confidently binned and uncertain sequence data objects from the community for subsequent biological interpretation. The binning of metagenome sequence fragments according to thresholds in the degree of membership opens the door for the identification of horizontally transferred elements and other genomic regions of uncertain assignment in which biologically meaningful information resides. The reported approach improves the unsupervised genome demarcation of populations within complex communities, increases the confidence in the coherence of the binned elements, and enables the identification of evolutionary processes ignored in hard-binning approaches in shotgun metagenomic studies.

Use of rituximab as an induction therapy in anti-glomerular basement-membrane disease

BACKGROUND

Anti-glomerular basement-membrane (anti-GBM) disease (or Goodpasture disease) is characterized by severe kidney and lung involvement. Prognoses have improved with treatments that combine plasma exchange and immunosuppressive drugs. However, patients with severe renal involvement can have poor renal outcomes and cyclophosphamide can cause significant complications. Anti-GBM antibodies have a direct pathogenic effect on the disease: thus, therapeutics that can decrease their production, such as rituximab, could be a good alternative.

METHODS

The medical files of five patients that had received rituximab as a first-line therapy (instead of cyclophosphamide), plus plasma exchange and steroids, were reviewed. All patients had severe disease manifestations.

RESULTS

Four patients required dialysis at diagnosis and remained dialysis-dependent over the mean follow-up of 15 months. Three patients had pulmonary involvement, but recovered even though mechanical ventilation was required. Anti-GBM antibodies became rapidly undetectable in all patients. One infectious and two hematological complications were observed.

CONCLUSIONS

We report the outcomes of five patients with Goodpasture disease and treated with rituximab as a first-line treatment. This strategy was effective at treating pulmonary manifestations and was associated with a good biological response with no major serious adverse events. However, renal outcomes were not significantly improved.

[Lethal Lyell's syndrome induced by fusidic acid]

BACKGROUND

Herein, we report the first case of toxic epidermal necrosis due to oral fusidic acid having a fatal outcome.

PATIENTS AND METHODS

An 82-year-old woman was referred to our dermatology department for generalized bullous skin eruption. Clinical examination showed fever, oral and ocular ulcerations, and epidermal detachment involving more than 70 % of her body surface area together with a positive Nikolsky sign. Lyell's syndrome was diagnosed. Cutaneous histology showed total epidermal necrosis and a normal dermis. Oral fusidic acid had been prescribed 12 days earlier for a chronic sacral pressure sore. No other treatment had been introduced during the previous two months. The outcome was fatal within 24 hours.

DISCUSSION

Fusidic acid is commonly used topically by dermatologists for limited staphylococcal skin infections. Oral treatment is rare and is recommended only for skin, bone or joint infections. This is the first reported case of toxic epidermal necrolysis due to oral fusidic acid. The French national drug safety monitoring register contains only one case in which fusidic acid was a possible culprit.

CONCLUSION

Fusidic acid must be considered a potential source of serious cutaneous adverse reactions, particularly toxic epidermal necrolysis.

[Acantholytic dermatosis in patients treated by vemurafenib: 2 cases]

BACKGROUND

Acantholytic dyskeratosis under BRAF inhibitors are dermatological diseases rarely reported to date.

PATIENTS AND METHODS

We report 2 cases of acantholytic dyskeratosis, reaching the trunk and the seborrheic zones, not itchy, appeared one month after the introduction of vemurafenib. The histological analysis was typical of a "Grover-like rash" for the 2 patients.

DISCUSSION

The appearance of acantholytic dyskeratosis under vemurafenib, a BRAF inhibitor, seems related with a paradoxical activation of the MAP-kinases pathway and with a growth acceleration of lesions in which RAS mutations of keratinocytes. Theses dermatoses seem also to occur with dabrafenib.

CONCLUSION

The patients treated by BRAF inhibitors (vemurafenib and dabrafenib) can present acantholytic dyskeratosis. The arisen of this mild dermatosis does not question, of course, the continuation of the treatment. These cutaneous manifestations can be managed with emollients.

Erosion of functional independence early in the evolution of a microbial mutualism

Many species have evolved to function as specialized mutualists, often to the detriment of their ability to survive independently. However, there are few, if any, well-controlled observations of the evolutionary processes underlying the genesis of new mutualisms. Here, we show that within the first 1,000 generations of initiating independent syntrophic interactions between a sulfate reducer (Desulfovibrio vulgaris) and a hydrogenotrophic methanogen (Methanococcus maripaludis), D. vulgaris frequently lost the capacity to grow by sulfate respiration, thus losing the primary physiological attribute of the genus. The loss of sulfate respiration was a consequence of mutations in one or more of three key genes in the pathway for sulfate respiration, required for sulfate activation (sat) and sulfate reduction to sulfite (apsA or apsB). Because loss-of-function mutations arose rapidly and independently in replicated experiments, and because these mutations were correlated with enhanced growth rate and productivity, gene loss could be attributed to natural selection, even though these mutations should significantly restrict the independence of the evolved D. vulgaris. Together, these data present an empirical demonstration that specialization for a mutualistic interaction can evolve by natural selection shortly after its origin. They also demonstrate that a sulfate-reducing bacterium can readily evolve to become a specialized syntroph, a situation that may have often occurred in nature.

Propagation-inside-layer-expansion method combined with physical optics for scattering by coated cylinders, a rough layer, and an object below a rough surface

In this article, the fields scattered by coated cylinders, a rough layer, and an object below a rough surface are computed by the efficient propagation-inside-layer-expansion (PILE) method combined with the physical optics (PO) approximation to accelerate the calculation of the local interactions on the non-illuminated scatterer, which is assumed to be perfectly conducting. The PILE method is based on the method of moments, and the impedance matrix of the two scatterers is then inverted by blocks from a Taylor series expansion of the inverse of the Schur complement. Its main interest is that it is rigorous, with a simple formulation and a straightforward physical interpretation. In addition, one of the advantages of PILE is to be able to hybridize methods (rigorous or asymptotic) valid for a single scatterer. Then, in high frequencies, the hybridization with PO allows us to significantly reduce the complexity in comparison to a direct lower-upper inversion of the impedance matrix of the two scatterers without loss in accuracy.

Polarized infrared reflectivity of one-dimensional Gaussian sea surfaces with surface reflections

Sea surface infrared reflectivity is an important parameter in maritime remote sensing. Usually, single reflection by the sea surface is considered. However, a loss of energy is then reported for large zenith observation angles (θ>50°) with a peak of about 4% for θ≈80°, because of the neglect of the multiple surface reflections. This paper presents calculations for the polarized infrared reflectivity of one-dimensional sea surfaces (2D problems) with two surface reflections, by introducing a bistatic illumination function with two reflections. The results show good agreement with the ones obtained by a Monte Carlo ray-tracing method. It is also shown that the energy conservation criterion is better satisfied after considering two surface reflections.

Polarized infrared emissivity of one-dimensional Gaussian sea surfaces with surface reflections

Surface reflection is an important phenomenon that must be taken into account when studying sea surface infrared emissivity, especially at large observation angles. This paper models analytically the polarized infrared emissivity of one-dimensional sea surfaces with shadowing effect and one surface reflection, by assuming a Gaussian surface slope distribution. A Monte Carlo ray-tracing method is employed as a reference. It is shown that the present model agrees well with the reference method. The emissivity calculated by the present model is then compared with measurements. The comparisons show that agreements are greatly improved by taking one surface reflection into account. The Monte Carlo ray-tracing results of sea surface infrared emissivity with two and three reflections are also determined. Their contributions are shown to be negligible.

Unpolarized emissivity of thin oil films over anisotropic Gaussian seas in infrared window regions

In this paper, we derive the unpolarized infrared (IR) emissivity of thin oil films over anisotropic Gaussian seas from a refined physical surface spectrum model of damping due to oil. Since the electromagnetic wavelength is much smaller than the surface mean curvature radius and than the surface root mean square height, the Kirchhoff-tangent plane approximation, reduced to the geometric optics approximation, can be used. The surface can then be replaced by its local infinite tangent plane at each point of each rough surface. The multiple reflections at each interface are ignored (i.e., for both the upper air/oil interface and the lower oil/sea interface of the contaminated sea). Nevertheless, the multiple reflections between the upper and the lower interfaces of the oil film are taken into account, by assuming a locally flat and planar thin oil film, which forms a local Fabry-Perot interferometer. This means that the Fresnel reflection coefficient of a single interface can be substituted for the equivalent Fresnel reflection coefficient of the air/oil/sea film, calculated by considering an infinite number of reflections inside the layer. Comparisons of the emissivity between a clean sea and a contaminated sea are presented, with respect to emission angle, wind speed, wind direction, oil film thickness, oil type, and wavelength. Thus, oil detection, characterization, and quantization are investigated in the IR window regions.

Scattering from very rough layers under the geometric optics approximation: further investigation

Scattering from very rough homogeneous layers is studied in the high-frequency limit (under the geometric optics approximation) by taking the shadowing effect into account. To do so, the iterated Kirchhoff approximation, recently developed by Pinel et al. [Waves Random Complex Media17, 283 (2007)] and reduced to the geometric optics approximation, is used and investigated in more detail. The contributions from the higher orders of scattering inside the rough layer are calculated under the iterated Kirchhoff approximation. The method can be applied to rough layers of either very rough or perfectly flat lower interfaces, separating either lossless or lossy media. The results are compared with the PILE (propagation-inside-layer expansion) method, recently developed by Déchamps et al. [J. Opt. Soc. Am. A23, 359 (2006)], and accelerated by the forward-backward method with spectral acceleration. They highlight that there is very good agreement between the developed method and the reference numerical method for all scattering orders and that the method can be applied to root-mean-square (RMS) heights at least down to 0.25lambda.

Metabolic modeling of a mutualistic microbial community

The rate of production of methane in many environments depends upon mutualistic interactions between sulfate-reducing bacteria and methanogens. To enhance our understanding of these relationships, we took advantage of the fully sequenced genomes of Desulfovibrio vulgaris and Methanococcus maripaludis to produce and analyze the first multispecies stoichiometric metabolic model. Model results were compared to data on growth of the co-culture on lactate in the absence of sulfate. The model accurately predicted several ecologically relevant characteristics, including the flux of metabolites and the ratio of D. vulgaris to M. maripaludis cells during growth. In addition, the model and our data suggested that it was possible to eliminate formate as an interspecies electron shuttle, but hydrogen transfer was essential for syntrophic growth. Our work demonstrated that reconstructed metabolic networks and stoichiometric models can serve not only to predict metabolic fluxes and growth phenotypes of single organisms, but also to capture growth parameters and community composition of simple bacterial communities.

Évaluation du suivi dermatologique et des tumeurs cutanées chez les greffés rénaux

BACKGROUND

Renal transplant patients are at increased risk for warts, actinic keratoses and carcinomas. A descriptive study was conducted to investigate the number and frequency of dermatologic examinations in renal transplant patients with a functional graft. The incidence and clinical factors for skin tumours were also assessed.

PATIENTS AND METHODS

We sent an initial questionnaire to 686 renal transplant patients asking whether they had consulted a dermatologist since the time of transplantation. A second questionnaire was then sent to private dermatologists in order to evaluate dermatologic follow-up and the frequency and anatomic distribution of warts and cancerous skin lesions. At the same time, the patients' medical records at the hospital were studied.

RESULTS

About two thirds of the 436 patients included in the study have seen a dermatologist at least once since the time of transplantation. Only 31.2% are being followed up regularly by a dermatologist. The incidence of warts and actinic keratoses is 48.8% and 20.6% respectively, and increases with the duration of immunosuppressive therapy. The incidence of carcinomas is 20.2%, with basal cell carcinomas being seen more frequently than other carcinomas. Risk factors identified for carcinomas are older age at transplantation, duration of immunosuppressive therapy, fair skin, presence of warts and actinic keratoses. All these skin lesions arise predominantly on highly sun-exposed surfaces. Nevertheless, squamous cell carcinomas are more often confined to sun-exposed skin than Bowen's diseases and basal cell carcinomas.

DISCUSSION

Dermatologic follow-up of transplant recipients has rarely been investigated and our study shows that monitoring of skin cancer is probably inadequate. It also confirms the high incidence of carcinomas among renal-transplant recipients in a temperate climate, although basal cell carcinomas are more frequent than squamous cell carcinomas.

Energy conservation of the scattering from one-dimensional random rough surfaces in the high-frequency limit

Energy conservation of the scattering from one-dimensional strongly rough dielectric surfaces is investigated using the Kirchhoff approximation with single reflection and by taking the shadowing phenomenon into account, both in reflection and transmission. In addition, because no shadowing function in transmission exists in the literature, this function is presented here in detail. The model is reduced to the high-frequency limit (or geometric optics). The energy conservation criterion is investigated versus the incidence angle, the permittivity of the lower medium, and the surface rms slope.

[Fluindione-induced acute exanthematous pustulosis with renal involvement]

INTRODUCTION

Fluindione (Previscan) is an oral anti-vitamin K anticoagulant, widely prescribed in France. Contrary to phenindione, which is also an indanedione derivative, very few cases of immunoallergic reactions have been described.

CASE REPORT

A 68 year-old man, treated with fluindione for cardiac arrhythmia, presented with a pustular eruption and erythema twenty days after initiation of treatment. The eruption was associated with hyperthermia, arthralgia, neutrophilia (11,000/mm2), hepatic cytolysis and renal involvement including acute renal failure, hematuria and proteinuria. In view of the absence of any earlier case in the literature, we did not impute fluindione and the drug was reintroduced and led to the rapid recurrence of all the same manifestations.

DISCUSSION

These manifestations were consistent with an immunoallergic reaction to fluindione (probable intrinsic imputability I3) and acute interstitial nephritis (probable intrinsic imputability I3). We believe this is the first case of acute generalized exanthematous pustulosis induced by fluindione (intrinsic imputability Bo). A few rare cases of fluindione-induced hypersensitivity reactions and acute interstitial nephritis, however, have been described.

Genes for the cytoskeletal protein tubulin in the bacterial genus Prosthecobacter

Tubulins, the protein constituents of the microtubule cytoskeleton, are present in all known eukaryotes but have never been found in the Bacteria or Archaea. Here we report the presence of two tubulin-like genes [bacterial tubulin a (btuba) and bacterial tubulin b (btubb)] in bacteria of the genus Prosthecobacter (Division Verrucomicrobia). In this study, we investigated the organization and expression of these genes and conducted a comparative analysis of the bacterial and eukaryotic protein sequences, focusing on their phylogeny and 3D structures. The btuba and btubb genes are arranged as adjacent loci within the genome along with a kinesin light chain gene homolog. RT-PCR experiments indicate that these three genes are cotranscribed, and a probable promoter was identified upstream of btuba. On the basis of comparative modeling data, we predict that the Prosthecobacter tubulins are monomeric, unlike eukaryotic alpha and beta tubulins, which form dimers and are therefore unlikely to form microtubule-like structures. Phylogenetic analyses indicate that the Prosthecobacter tubulins are quite divergent and do not support recent horizontal transfer of the genes from a eukaryote. The discovery of genes for tubulin in a bacterial genus may offer new insights into the evolution of the cytoskeleton.

Proteinuria and the expression of the podocyte slit diaphragm protein, nephrin, in diabetic nephropathy: effects of angiotensin converting enzyme inhibition

AIMS/HYPOTHESIS

Proteinuria, reflecting increased glomerular permeability to macromolecules is a characteristic feature of diabetic nephropathy. Nephrin, a 1241-residue transmembrane protein is a key component of the podocyte slit pore membrane and a major contributor of the glomerular filtration barrier. We investigated the expression of nephrin in human kidney tissue from patients with diabetic nephropathy to elucidate its relationship with proteinuria and the effects of anti-proteinuric therapy with angiotensin converting enzyme inhibition.

METHODS

Renal biopsies were examined from 14 patients with Type II (non-insulin-dependent) diabetes mellitus and proteinuria who had been randomised to receive treatment with the ACE inhibitor, perindopril (4 mg/day) or placebo for the preceding 2 years. These specimens were compared with control human tissue sections, obtained from areas of normal renal cortex following nephrectomy for malignancy. Proteinuria was measured, specimens were examined histologically for injury and the expression of nephrin messenger RNA was assessed by quantitative in situ hybridisation.

RESULTS

Glomeruli from placebo-treated patients with diabetic nephropathy, showed a 62% reduction in nephrin expression compared with control subjects (p=0.0003). In contrast, nephrin RNA in glomeruli from perindopril treated patients was similar to that in the non-diabetic control group. In both placebo and perindopril treated patients, a close inverse correlation was noted between the magnitude of nephrin gene expression and the degree of proteinuria (placebo: r=0.86, p=0.013, perindopril: r=0.91, p=0.004).

CONCLUSION/INTERPRETATION

Modulation in nephrin expression is related to the extent of proteinuria in diabetic nephropathy. These changes define, at a molecular level alterations in the glomerulus that occur in relation to proteinuria in diabetes and the effects of anti-proteinuric treatment with ACE inhibition.

Does ACE inhibition slow progression of glomerulopathy in patients with Type 2 diabetes mellitus?

AIMS

To examine the effect of ACE inhibition on glomerular structure in Type 2 diabetic patients with nephropathy.

METHODS

Twenty-two patients were randomized to receive either perindopril (PE) or placebo (PO) and biopsied at baseline and after 2 years. Nineteen patients completed the study and data on interstitial changes, examined by light microscopy, have already been published. Only 11 patients (five PE, six PO) had sufficient tissue at baseline and follow-up to provide material for detailed electron microscopic examination.

RESULTS

At baseline, mean +/- sd age (PE vs. PO) was 48 +/- 12 vs. 45 +/- 7 years; creatinine clearance 116 +/- 24 vs. 128 +/- 68 ml/min; median (range) proteinuria 0.7 (0.1-1.0) vs. 0.5 (0.07-3.9) g/24 h (P = NS for all). This cohort of 11 patients showed the same interstitial changes as the whole group. Between-group analysis showed that the change in interstitial volume fraction was significantly greater in the PO compared with PE group (0.10 +/- 0.07 vs. -0.001 +/- 0.04, P = 0.020). There were no significant changes in proteinuria or glomerular structural parameters (mesangial volume fraction PO 0.40 +/- 0.17 to 0.42 +/- 0.21; PE 0.29 +/- 0.08 to 0.28 +/- 0.14) in either treatment group.

CONCLUSIONS

Interstitial changes appear to be more sensitive to ACE inhibition than glomerulopathy. Larger patient groups and longer treatment periods are necessary in order to detect any possible impact of ACE inhibition on the glomerular changes in Type 2 diabetes mellitus.

Dag-1 carcinoma cell in studying the mechanisms of progression and therapeutic resistance in bladder cancer

OBJECTIVE

We describe a new human bladder carcinoma cell line (DAG-1) established from a resected bladder cancer fragment and maintained in culture for more than 5 years and over 300 passages.

METHODS AND RESULTS

Immunological, biochemical and molecular analysis showed that the DAG-1 cells (62 chromosomes) express the cytokeratines 8, 13, 18 and 20 that confirm their epithelial origin as well as numerous cytokine and cytokine receptor mRNAs. They secrete tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), plasminogen activator inhibitors (PAI-1 and PAI-2), and express u-PA receptors (u-PAR/CD87) at their surface. DAG-1 cells are resistant to TNFalpha- and IFNgamma-induced apoptosis, two cytokines secreted in the urine of Calmette-Guérin bacillus-treated patients and involved in the tumor regression.

CONCLUSION

The DAG-1 cell line is a useful tool, both in vitro and in vivo, to study the progression of bladder tumors and their mechanisms of resistance to immunotherapy in relation with PAI-2 and antioxidant enzymes.

[Heterogeneity of nephropathies in type 2 diabetes]

DIVERSE KIDNEY DISORDERS: Patients with type 2 diabetes mellitus who develop nephropathy can have various types of disorders capable of progressively destroying the kidneys. It is now clear that the same type of diffuse or nodular glomerulosclerosis develops irrespective of the type of diabetes, i.e. the pathophysiology of hyperglycemia. HETEROGENEITY: There is however a certain degree of heterogeneity in terms of clinical presentation, clinical course and response to treatment. Heterogeneity is due to age, the number of different accumulated risk factors and disease states, genetic factors that are in the process of being identified, and finally, lesions to the urologic apparatus, the arteries, and the renal parenchyma itself that are not directly caused by diabetes. PRACTICAL IMPACT: Mixed lesions, due to both diabetic and non-diabetic causes, may therefore exist in the same kidney. These different possibilities should be systematically considered in order to adopt an individualized investigative and therapeutic attitude for each new patient.

Human herpesvirus 8 and Epstein Barr-virus in a cutaneous B-cell lymphoma and a malignant cell line established from the blood of an AIDS patient

Human Herpesvirus 8 (HHV-8) has been consistently associated with Primary Effusion Lymphoma (PEL or body-cavity-based lymphoma) but not with other lymphomas. This paper reports on an AIDS patient without obvious malignant effusion in body cavities but with a cutaneous lymphoma where HHV-8 and Epstein-Barr virus (EBV) were detected by PCR and electron microscopy. Both viruses were also detected in all the cells of a malignant cell line (BBG1) established from the patient's peripheral blood mononuclear cells. As in PEL and PEL-derived cell lines, both the tumor and the lines lacked B-antigen expression in immunological studies but were of the same B origin as shown by clonal immunoglobulin gene rearrangements. In contrast to other co-infected cell lines, BBG1 and subclones spontaneously expressed the HHV-8 lytic antigens p40, p27, p60 and the EBV transforming latent antigen EBNA2. These data suggest that the clinical and biological features of HHV-8-and EBV-associated lymphomas could be wider than has been described to date in PEL particularly with the in vivo presence of circulating malignant dually-infected cells engaged in a spontaneous HHV-8 lytic infection.

Expansion of cortical interstitium is limited by converting enzyme inhibition in type 2 diabetic patients with glomerulosclerosis. The Diabiopsies Group

Renal interstitial expansion is now considered a useful marker of progression of several nephropathies. This study describes a multicenter, prospective, double-blind, placebo-controlled, randomized trial of the effects of Perindopril (4 mg/d) on kidney structure and function over 2 yr in 26 type 2 diabetic patients with proteinuria ranging from 70 to 4210 mg/d and relatively preserved GFR (creatinine clearance >60 ml/min). All patients underwent baseline renal biopsy, but four (15%) were not randomized because of the presence of nondiabetic nephropathy. The remaining 22 were randomized ( 11 to Perindopril [PE], 11 to placebo [PO]), and 19 (9 PE, 10 PO) underwent follow-up biopsy at 2 yr. BP was controlled equally in both groups throughout. Proteinuria increased in PO patients (+1562 mg/d) but declined in PE patients (-156 mg/d) (P < 0.05). Morphometric analysis was performed by light microscopy using a Biocom computer. Over the 2 yr, mean cortical interstitial fractional volume identical at baseline increased significantly in PO patients (31.7 +/- 5.3 versus 40.2 +/- 11.1%; P = 0.001) but was unchanged in PE patients (33.8 +/- 4.9 versus 34.7 +/- 6.6%; P = 0.50). It is concluded that: (1) nondiabetic nephropathy is present in approximately 15% of albuminuric type 2 diabetic patients; and (2) Perindopril prevents interstitial expansion in hypertensive patients with biopsy-proven diabetic glomerulopathy. These results support a role of angiotensin II in the progression of interstitial changes in type 2 diabetic patients with nephropathy.

Hunter's syndrome and associated sleep apnoea cured by CPAP and surgery

A 42-yr-old male with Hunter's syndrome presented with severe obstructive sleep apnoea syndrome (OSAS) and daytime respiratory failure. Continuous positive airway pressure (CPAP) therapy was initially ineffective and produced acute respiratory distress. Extensive Hunter's disease infiltration of the upper airway with a myxoma was confirmed. Following surgery to remove the myxoma at the level of the vocal cords, CPAP therapy was highly effective and well tolerated. This report demonstrates the necessity of evaluating fully the upper airway in patients with unusual variants of OSAS, particularly where the disease is not adequately controlled by CPAP.

Oncocytoma of the eyelid: an aggressive benign tumor

OBJECTIVE

The authors report the case of an 83-year-old patient with a benign oncocytoma of the inferior eyelid.

DESIGN

INTERVENTIONal case report.

INTERVENTION

Treatment consisted of a large orbital exenteration followed by reconstruction with a pedicled temporalis muscle flap.

MAIN OUTCOME MEASURES

Histologic evaluation and clinical follow-up were measured.

RESULTS

After a year of follow-up, there was no sign of local recurrence.

CONCLUSIONS

Oncocytomas, even if benign, must be considered as very aggressive tumors and treated accordingly.

Successful renal transplantation in Jeune syndrome type 2

Jeune syndrome (asphyxiating thoracic dystrophy) is a rare inherited disease which is fatal in early childhood in 70% of cases. Severe renal involvement may occur and lead to chronic renal insufficiency in patients who survive respiratory failure. Therefore the opportunity to perform kidney transplantation is quite rare. We report a successful cadaver renal transplantation in a 10-year-old boy with Jeune syndrome type 2.

Clear cell tumor of the lung: an immunohistochemical and ultrastructural study supporting a pericytic differentiation

Clear cell tumor ("sugar tumor") of the lung is a rare benign lesion with unclear histogenesis. It is composed of large cells with a clear cytoplasm rich in glycogen, blended with an abundant network of sinusoid-type vessels. We report two cases of sugar tumor, one of these lacking clearly demonstrable glycogen storage. In both, the tumor cells lacked keratin expression and were positive for vimentin and HMB 45, an antibody recognizing perivascular or myoid cell proliferation such as lymphangioleiomyomatosis and angiomyolipoma. The tumor cells were also immunoreactive for an endothelial cell marker, CD 34, but negative for Factor VIII or smooth muscle actin. Intercellular deposition of basal-like material was immunostained with Type IV collagen. At ultrastructural examination of one of these cases, tumor cells showing features of pericytes or poorly differentiated perivascular leiomyocytes encased in basement material were observed in close association with endothelial cells; their cytoplasm contained numerous membrane-bound glycogen and pinocytic vesicles. We conclude that on the basis of immunohistochemical and ultrastructural phenotype, sugar tumor presents pericytic features and that glycogen storage is not a constant feature of these benign tumors.

Malignant peripheral nerve sheath tumor arising in a "de novo" ganglioneuroma: a case report and review of the literature

A case of a "de novo" ganglioneuroma showing a large area of malignant peripheral nerve sheath tumor (MPNST) is described. The tumor arose in an 11.5-year-old girl with neither stigmata nor family history of von Recklinghausen's neurofibromatosis. In addition, the patient had no previous history of a neuroblastoma or radiation therapy. This report provides new evidence that, although rare, the spontaneous development of an MPNST in a benign ganglioneuroma can occur. Immunohistochemical and electron microscopy studies supported the finding that the spindle cell component was of nerve sheath origin.

Schwannoma of the bulbar conjunctiva

We describe a conjunctival tumor that occurred in the limbic region of the left eye in a 37-year-old man. The mass was located beneath the conjunctival epithelium. It consisted of a well-demarcated proliferation of fusiform cells arranged in bundles in a fibrous stroma. Tumor cells strongly expressed S-100 protein. On ultrastructural analysis, the tumor was composed of Schwann cells surrounded by a continuous basal lamina. These data led to the rare diagnosis of conjunctival schwannoma.

[Neurothekeoma. General review apropos of an anatomoclinical case with immunohistochemical and ultrastructural study]

The authors report a case of neurothekeoma in a 16-year-old woman. The tumor was located in the dermis of the chin and exhibited a plexiform and multinodular architecture with dense lobules admixed with myxoid areas. Tumor cells were pleomorphic and few atypias and mitoses were seen. On immunohistochemical study, intracytoplasmic staining was observed with anti-vimentin antibody, and, to a lesser extent, with KP1 antibody. Few elements expressed S100 protein. Ultrastructural analysis showed undifferentiated mesenchymal cells. A review of 156 cases (of which 123 cases are reported in two main series) shows that neurothekeoma preferentially affects dermis in cervicofacial areas and shoulders in young women. It has a benign course and recurrence is not seen provided excision is complete. Two main histological varieties are described, i.e. cellular and myxoid, the latter being referred to as nerve sheath myxoma. Diagnostic problems can be raised with other nerve sheath tumors and melanocytic and fibrohistiocytic proliferations. Transition forms between neurothekeoma and neurinoma or neurofibroma are described. Despite confusing immunohistochemical and ultrastructural data, most authors admit that neurothekeoma can express schwannian or perineurial differentiations, and may also be derive from an undifferentiated mesenchymal cell of neural crest origin.

Ultrastructural localization of the major components of the extracellular matrix in normal rat nerve

In this study we determined the ultrastructural distribution of the various components of the extracellular matrix (laminin, fibronectin, Type I, III, and IV collagens) of the normal peripheral nerve in adult rat. The localization of these macromolecules was investigated in basement membranes as well as in different areas of epi-, peri-, and endoneurium, by use of a pre-embedding immunoperoxidase method.