Mandibular osteonecrosis following herpes zoster infection: Report of a rare case with a literature review

Any patient with a herpes zoster infection of the mandibular branch of the trigeminal nerve should benefit from early oral monitoring, especially in elderly population where traumatic dental prostheses are common, because osteonecrosis can occur.

[An unexpected discovery of laryngeal neurofibroma during intubation for elective surgery]

We report the unexpected discovery of a large laryngeal neurofibroma during a direct laryngoscopy for intubation in a 18-year old female with a medical history of neurofibromatosis type 1. The most striking feature of this case report is the discrepancy between the absence of clinical manifestations and the size and location of the neurofibroma. This case highlights the importance of a careful preoperative assessment, especially in the context of multisystemic disease. Knowledge of the disease, recognition of related complications and adequate preoperative evaluation are crucial to establish the safest anesthesia strategy.

Multiple gingival metastasis of renal cell carcinoma: a case report

Introduction: Oral metastases are rare and represent only 1% of malignant diseases of the oral cavity, but they are often associated with poor prognosis. The primary tumor is recognizable in most cases; however, in 27.6% of cases, metastasis is the first clinical manifestation. Observation: An 82-year-old consulted for the recent appearance of a 1-cm-wide gingival tumor on 46. Since this patient had metastatic clear cell renal cell carcinoma, oral metastasis was confirmed by histopathology. In the following weeks, other oral metastases appeared. Palliative radiotherapy was the chosen treatment option, but the patient died before he could benefit from it. Discussion: Multiple oral metastases are rare, and metastasis of renal origin is not the most frequently encountered. The metastatic dissemination pathway described is hematogenous or lymphatic. Diagnosis is often easy if the primary tumor is already identified, but is a challenge if it is not, because the lesion often has a nonspecific appearance. Different surgical, radiotherapeutic, and medical therapeutic options exist, but are often palliative. A new immunotherapy route is under development and looks promising in the treatment of renal cell carcinoma. Conclusions: Oral metastasis often has poor prognosis, and management of the lesion is problematic. However, current research suggests a therapeutic and prognostic improvement.

Avascular osteonecrosis of the premaxilla secondary to disseminated intravascular coagulation: a case report

Introduction:Disseminated intravascular coagulation (DIC) is a complexe systemic disorder characterized by a widespread activation of the coagulation, that may lead to thrombosis, ischemia and finally, end-organ failure. The clinical presentation of DIC depends on the site of intravascular coagulation and the severity of the disease process. Avascular osteonecrosis is a pathological state, that can occur secondary to DIC and where a reduced vascular supply leads to ischemia and bone necrosis.Observation:A 83 years old patient was sent to the oral surgery department for tooth mobility in the premaxilla, following the diagnosis of sepsis and DIC induced acute myeloid leukemia, one month ago. The examination showed an exposed avascular bone behind the 12-11-21. A diagnosis of DIC induced osteonecrosis of the premaxilla was made. A resection surgery was then programmed.Discussion:DIC may generates thrombi that might occlude intraosseous vessels in the premaxilla, and lead to bone necrosis. The maxilla is supplied by multiple branches of external carotide artery, therefore, usually, there is a lower risk of osteonecrosis in the maxilla. Nevertheless, since 1993, 4 cases of avascular necrosis of the maxilla secondary to DIC are repported in literature.Conclusion:This kind of complication, although being rare, can be dramatic for the patient as bone and aesthetic defects. Early support and management of these complications is necessary.

Massive bleeding after a tooth extraction: Diagnosis of unknown arteriovenous malformation of the mandible, a case report

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Mandibular arteriovenous malformation (AVM) are very unusual condition.

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They remain frequently undiagnosed until a severe bleeding occurs during an oral surgical procedure.

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This case was a real diagnostical challenge: clinical presentation and initial radiographic examination was atypical.

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Curently there is no guideline to manage this kind of pathology.

Introduction

Arteriovenous malformations (AVMs) are very rare. Only 5% of them occurs in the jaws but they can manifest with dramatic bleeding and be life-threatening.

Presentation of case

We report the case of a 11-year-old healthy girl who presented a massive hemorrhage after extraction of the right mandibular first primary molar. This patient received a blood transfusion and was hospitalized in pediatric intensive care unit. CT angiography highlighted an AVM of the mandible. Treatment consisted in selective embolization.

Discussion

A review of the literature shows that the majority of AVMs of the jaws are often unknown until severe bleeding occurs during dental surgery. The low specificity of radiological signs on panoramic radiography makes the diagnosis particularly challenging. Their management requires an interdisciplinary approach. Selective embolization has a place of choice in the treatment of these complex pathologies.

Conclusion

Although AVMs of the jaws are rare, they are frequently revealed through a massive hemorrhage during tooth extraction. Dentists have to suspect them when young patients present some clinical features, as spontaneous gingival bleeding, unexplained dental mobility, or facial asymmetry.

Patterns of metal distribution in hypersaline microbialites during early diagenesis: Implications for the fossil record

The use of metals as biosignatures in the fossil stromatolite record requires understanding of the processes controlling the initial metal(loid) incorporation and diagenetic preservation in living microbialites. Here, we report the distribution of metals and the organic fraction within the lithifying microbialite of the hypersaline Big Pond Lake (Bahamas). Using synchrotron-based X-ray microfluorescence, confocal, and biphoton microscopies at different scales (cm-μm) in combination with traditional geochemical analyses, we show that the initial cation sorption at the surface of an active microbialite is governed by passive binding to the organic matrix, resulting in a homogeneous metal distribution. During early diagenesis, the metabolic activity in deeper microbialite layers slows down and the distribution of the metals becomes progressively heterogeneous, resulting from remobilization and concentration as metal(loid)-enriched sulfides, which are aligned with the lamination of the microbialite. In addition, we were able to identify globules containing significant Mn, Cu, Zn, and As enrichments potentially produced through microbial activity. The similarity of the metal(loid) distributions observed in the Big Pond microbialite to those observed in the Archean stromatolites of Tumbiana provides the foundation for a conceptual model of the evolution of the metal distribution through initial growth, early diagenesis, and fossilization of a microbialite, with a potential application to the fossil record.

[Primary localized cutaneous nodular amyloidosis: A diagnostic and therapeutic challenge]

BACKGROUND

Nodular primary localized cutaneous amyloidosis (PLCA) is a rare subtype of localized cutaneous amyloidosis in which amyloid protein is derived from immunoglobulin light chains. Follow-up for progression to systemic amyloidosis or autoimmune disease is mandatory. No consensus exists regarding treatment.

PATIENTS AND METHODS

We report a case of nodular PLCA in a 49-year-old man, presenting as an asymptomatic nodule of the nose. Skin biopsy revealed diffuse deposition of amyloid associated with plasmocyte proliferation. Monotypic kappa light-chain restriction was observed. Extensive systemic evaluation, including bone marrow biopsy and PET scan, was negative. Protein electrophoresis and immunofixation in serum and urine were normal. The nodule was treated with radiotherapy but there was no response. Mohs micrographic surgery (MMS) was performed with no recurrence at 6 months of follow-up. No systemic progression was observed one year after the initial diagnosis.

DISCUSSION

Since nodular PLCA may have a cutaneous presentation similar to that of primary systemic amyloidosis, evaluation for systemic amyloidosis is necessary. Treatment of amyloidosis is difficult. Radiotherapy appears ineffective in treating this type of primary cutaneous amyloidosis, and surgical treatment, where possible, is a good option, especially with MMS, which allows both controlled excision and minimal margins.

Organic and mineral imprints in fossil photosynthetic mats of an East Antarctic lake

Lacustrine microbial mats in Antarctic ice-free oases are considered modern analogues of early microbial ecosystems as their primary production is generally dominated by cyanobacteria, the heterotrophic food chain typically truncated due to extreme environmental conditions, and they are geographically isolated. To better understand early fossilization and mineralization processes in this context, we studied the microstructure and chemistry of organo-mineral associations in a suite of sediments 50-4530 cal. years old from a lake in Skarvsnes, Lützow Holm Bay, East Antarctica. First, we report an exceptional preservation of fossil autotrophs and their biomolecules on millennial timescales. The pigment scytonemin is preserved inside cyanobacterial sheaths. As non-pigmented sheaths are also preserved, scytonemin likely played little role in the preservation of sheath polysaccharides, which have been cross-linked by ether bonds. Coccoids preserved thylakoids and autofluorescence of pigments such as carotenoids. This exceptional preservation of autotrophs in the fossil mats argues for limited biodegradation during and after deposition. Moreover, cell-shaped aggregates preserved sulfur-rich nanoglobules, supporting fossilization of instable intracellular byproducts of chemotrophic or phototrophic S-oxidizers. Second, we report a diversity of micro- to nanostructured CaCO3 precipitates intimately associated with extracellular polymeric substances, cyanobacteria, and/or other prokaryotes. Micro-peloids Type 1 display features that distinguish them from known carbonates crystallized in inorganic conditions: (i) Type 1A are often filled with globular nanocarbonates and/or surrounded by a fibrous fringe, (ii) Type 1B are empty and display ovoid to wrinkled fringes of nanocrystallites that can be radially oriented (fibrous or triangular) or multilayered, and (iii) all show small-size variations. Type 2 rounded carbonates 1-2 μm in diameter occurring inside autofluorescent spheres interpreted as coccoidal bacteria may represent fossils of intracellular calcification. These organo-mineral associations support organically driven nanocarbonate crystallization and stabilization, hence providing potential markers for microbial calcification in ancient rocks.

Functional fixation of autotransplanted tooth germs by using bioresorbable membranes

OBJECTIVE

The purpose of this study was to evaluate the contribution of a bioresorbable membrane placement to the healing of immature teeth after autotransplantation of tooth buds.

STUDY DESIGN

Six cases were selected: 2 transplantations of wisdom teeth, 2 for premolar agenesis, 1 for ectopia, and 1 premolar in an incisor position. The crown of each tooth germ and the marginal alveolar bone were covered with a resorbable membrane.

RESULTS

The radicular edification was nearly complete, neither ankylosis nor inflammatory resorption was observable, the pulp vitality was preserved, and the periodontal integration was identical to that of other teeth. The membrane ensured contention and stabilization of the transplant, allowed functional stimulation, permitted protection of the coagulum and periodontal cells, and kept the epithelium at a distance.

CONCLUSIONS

The transplantations of immature teeth were improved by the use of a resorbable membrane, which caused an optimal functional fixation of the transplanted tooth.

Measurement of in situ phytoextraction of zinc by spontaneous metallophytes growing on a former smelter site

This work was undertaken to measure the in situ phytoextraction of zinc using a former zinc-smelter site where metallophyte plants have been growing for 30 years. The site exhibited a gradient in the total metal concentration in the upper horizon (from 3230 to 8530 mg Zn kg(-1)). Soils were sampled from four different sectors (I-IV), and plant shoots were harvested, identified, their biomass weighed and analysed for zinc. The results showed that three plant species were dominant on the site, including Arabidopsis halleri (cress), Armeria maritima (seathrift), and Arrhenatherum elatius (fromental). A. maritima was the predominant species according to the biomass production on the most polluted sector 1. As the concentration of metals in soils decreased. A. maritima disappeared and A. halleri increased. The biomass of A. elatius was the highest on the less polluted soils. Concentrations in zinc in the aerial parts of plants varied from 73 (sector IV) to 6269 mg kg(-1) DM (sector 1). The concentration of Zn in A. halleri decreased with the decrease in concentration of zinc in soil. Phytoextraction was calculated from the biomass and its concentration of metal. It was at a maximum in sector III with a high contribution of A. halleri and A. elatius and reached 10 kg Zn ha(-1), a promising amount for phytoextraction considering the absence of any agricultural practices. In sector 1, phytoextraction was four times lower despite a 2.6 times higher concentration of Zn in the upper horizon. In conclusion, phytoextraction was strongly dependent on the concentration of the available metal in soils which may limit the growth of plants, and favour tolerant but low biomass plant species such as A. maritima.

DNA protection mechanisms are not involved in the radioresistance of the hyperthermophilic archaea Pyrococcus abyssi and P. furiosus

Hyperthermophilic archaea of the genus Pyrococcus are resistant to gamma radiation, suggesting that efficient mechanisms for DNA repair exist in these organisms. To determine whether protective mechanisms might also be implicated in this radioresistance, we have estimated the linear density of DNA double-stranded breaks caused by gamma irradiation in the genomic DNA of two Pyrococcus species, using Escherichia coli and the radioresistant bacterium Deinococcus radiodurans as controls. The linear density of double-stranded breaks was essentially the same in all four microorganisms when irradiation was carried under similar anaerobic conditions, indicating that no specific DNA protection mechanisms exist in Pyrococcus species. Using one- and two-dimensional gel electrophoresis we compared the protein patterns from Pyrococcus abyssi and P. furiosus cells that had or had not been exposed to gamma rays. We did not detect any significant protein induction following DNA damage in either species.

Outgassing behavior and composition of comet C/1999 S4 (LINEAR) during its disruption

The gas activity of comet C/1999 S4 (LINEAR) was monitored at radio wavelengths during its disruption. A runaway fragmentation of the nucleus may have begun around 18 July 2000 and proceeded until 23 July. The mass in small icy debris (</=30-centimeter radius) was comparable to the mass in the large fragments seen in optical images. The mass budget after breakup suggests a small nucleus ( approximately 100- to 300-meter radius) that had been losing debris for weeks. The HNC, H2CO, H2S, and CS abundances relative to H2O measured during breakup are consistent with those obtained in other comets. However, a deficiency in CH3OH and CO is observed.

Isolation of a minD-like gene in the hyperthermophilic archaeon Pyrococcus AL585, and phylogenetic characterization of related proteins in the three domains of life

The region upstream of the dinF-like gene of the hyperthermophilic archaeon Pyrococcus strain AL585 has been cloned and sequenced. This region contains an open reading frame (ORF) that encodes a polypeptide with a high similarity to MinD proteins and their Mrp paralogues. Transcripts of the dinF-like and the minD-like genes were detected by RT-PCR, indicating that they are both expressed in vivo. The MinD and MinD-like proteins belong to a broad family of ATPases involved in chromosome and plasmid partitioning. MinD-like proteins can be defined by specific amino-acid sequence signatures. A systematic search for proteins sharing these signatures in current databases and newly sequenced genomes show that MinD-like proteins are present in all archaeal genomes sequenced so far, often in several copies. Phylogenetic analysis identifies two groups of MinD-like proteins which are also characterized by more conserved amino-acid motifs. A first group, which includes the Escherichia coli MinD and the Pyrococcus AL585 MinDL protein, contains only procaryotic proteins. This group can be further divided into a subgroup of archaeal proteins and two subgroups of bacterial proteins. A second group includes proteins more related to the E. coli Mrp protein and contains representants of the three domains of life. The conservation of MinD-like proteins in the three domains of life suggests that these proteins play a central role in cellular metabolism.

Evolution of the outgassing of comet Hale-Bopp (C/1995 O1) from radio observations

Spectra obtained from ground-based radio telescopes show the progressive release of CO, CH3OH, HCN, H2O (from OH), H2S, CS, H2CO, CH3CN, and HNC as comet Hale-Bopp (C/1995 01) approached the sun from 6.9 to 1.4 astronomical units (AU). The more volatile species were relatively more abundant in the coma far from the sun, but there was no direct correlation between overabundance and volatility. Evidence for H2O sublimation from icy grains was seen beyond 3.5 AU from the sun. The change from a CO-driven coma to an H2O-driven coma occurred at about 3 AU. The gas outflow velocity and temperature increased as Hale-Bopp approached the sun.

Substantial outgassing of CO from comet Hale-Bopp at large heliocentric distance

When comet C/1995 O1 (Hale-Boop) was discovered, at a distance of seven astronomical units from the sun, it was more than one hundred times brighter than comet Halley at the same distance. A comet's brightness is derived from the reflection of sunlight from dust grains driven away from the nucleus by the sublimation of volatile ices. Near the sun, sublimation of water ice (a main constituent of comet nuclei) is the source of cometary activity; but at its current heliocentric distance, Hale-Boop is too cold for this process to operate. Other comets have shown activity at large distances, and in the case of comet Schwassmann-Wachmann 1, carbon monoxide has been detected in quantities sufficient to generate its observed coma. Here we report the detection of CO emission from Hale-Boop, at levels indicating a very large rate of outgassing. Several other volatile species were searched for, but not detected. Sublimation of CO therefore appears to be responsible for the present activity of this comet, and we anticipate that future observations will reveal the onset of sublimation of other volatile species as the comet continues its present journey towards the sun.

[Malignant melanoma of the oral mucosa]

The oral cavity is a mave "localisation" for the malignant melanoma's development. Surgical excision with a wide margin is the treatment of choice for localized oral melanoma. The prognosis is particularly poor when metastasis occurs. One case is reported, in a alveolar site.