Intramolecular Hgπ interactions of d-character with non-bridging atoms in mercury-aryl complexes.

Mercury 5d-orbitals are involved in intramolecular π-interactions with carbon and sulfur nearest and next-nearest neighbors in mercury-aryl complexes. This unexpected character of the electron cloud of mercury was revealed by high energy-resolution XANES spectroscopy readily interpreted in terms of a final-state local (l,m)-projected density of states (DOS).

Tumor heterogeneity of fibroblast growth factor receptor 3 (FGFR3) mutations in invasive bladder cancer: implications for perioperative anti-FGFR3 treatment.

BACKGROUND: Fibroblast growth factor receptor 3 (FGFR3) is an actionable target in bladder cancer. Preclinical studies show that anti-FGFR3 treatment slows down tumor growth, suggesting that this tyrosine kinase receptor is a candidate for personalized bladder cancer treatment, particularly in patients with mutated FGFR3. We addressed tumor heterogeneity in a large multicenter, multi-laboratory study, as this may have significant impact on therapeutic response. PATIENTS AND METHODS: We evaluated possible FGFR3 heterogeneity by the PCR-SNaPshot method in the superficial and deep compartments of tumors obtained by transurethral resection (TUR, n = 61) and in radical cystectomy (RC, n = 614) specimens and corresponding cancer-positive lymph nodes (LN+, n = 201). RESULTS: We found FGFR3 mutations in 13/34 (38%) T1 and 8/27 (30%) ≥T2-TUR samples, with 100% concordance between superficial and deeper parts in T1-TUR samples. Of eight FGFR3 mutant ≥T2-TUR samples, only 4 (50%) displayed the mutation in the deeper part. We found 67/614 (11%) FGFR3 mutations in RC specimens. FGFR3 mutation was associated with pN0 (P < 0.001) at RC. In 10/201 (5%) LN+, an FGFR3 mutation was found, all concordant with the corresponding RC specimen. In the remaining 191 cases, RC and LN+ were both wild type. CONCLUSIONS: FGFR3 mutation status seems promising to guide decision-making on adjuvant anti-FGFR3 therapy as it appeared homogeneous in RC and LN+. Based on the results of TUR, the deep part of the tumor needs to be assessed if neoadjuvant anti-FGFR3 treatment is considered. We conclude that studies on the heterogeneity of actionable molecular targets should precede clinical trials with these drugs in the perioperative setting.

Natural attenuation of zinc pollution in smelter-affected soil.

Previous synchrotron X-ray microprobe measurements of Zn speciation in contaminated and uncontaminated soils have identified phyllosilicate as the main sequestration phase. The emphasis now is focused on comparing the nature and properties of neoformed and geogenic phyllosilicate species to understand natural attenuation processes. Refined structural characterization of the two types of Zn-containing phyllosilicate in slightly basic smelter-affected agricultural soils were obtained using a so far unprecedented combination of X-ray microscopic techniques, including fluorescence (µ-XRF), absorption (µ-EXAFS), and diffraction (µ-XRD), and X-ray bulk-sensitive techniques, including powder and polarized EXAFS spectroscopy. The unpolluted and polluted species are both dioctahedral smectites, but the first which contains minor Zn (ca. 150 mg/kg) is aluminous and Fe-free, and the second, which contains several hundreds to a few thousands mg/kg Zn depending on the distance to the smelter and wind direction, is ferruginous with an average Fe/Al atomic ratio of 1.1 ± 0.5. The Zn(2+) and Fe(3+) in the neoformed smectite are derived from the weathering of ZnS, ZnO, FeS(2), and ZnFe(2)O(4) particles from the smelter. These cations diffuse away from their particulate mineral sources and coprecipitate with Al and Si in the soil clay matrix. Zinc sequestration in the octahedral sheet of dioctahedral smectite is potentially irreversible, because this type of phyllosilicate is stable over a large pH range, and the neoformed species is analogous to the native species which formed over time during pedogenesis.

[Childhood septic temporomandibular arthritis]. / Arthrite septique temporomandibulaire de l'enfant.

OBJECTIVE: To report a clinical case of acute otitis media in a child, complicated by septic temporomandibular arthritis and to present a review of the literature. PATIENT AND METHODS: We report a case of a 7-year-old boy who presented an altered general condition, major hyperthermia, associated with a left temporozygomatic mass in a context of recurrent bilateral acute otitis media lasting for 2 months. Emergency computed tomodensitometry (CT scan) showed left temporomandibular joint arthritis. Treatment consisted of a parenteral double antibiotic therapy and prevention of temporomandibula (TM) ankylosis. RESULTS: After 20 months of follow-up, the child showed a normal ORL examination with no maxillofacial sequelae. CONCLUSION: All temporozygomatic masses presenting in a septic context should suggest the diagnosis of TM arthritis; computed tomodensitometry should be done immediately.

[Ecology and transmission of Mycobacterium ulcerans]. / Ecologie et mode de transmission de Mycobacterium ulcerans.

Mycobacterium ulcerans is an environmental pathogen concerning mainly the tropical countries; it is the causative agent of Buruli ulcer, which has become the third most important mycobacterial disease. In spite of water-linked epidemiological studies to identify the sources of M. ulcerans, the reservoir and the mode of transmission of this organism remain elusive. To determine the ecology and the mode of transmission of M. ulcerans we have set up an experimental model. This experimental model demonstrated that water bugs were able to transmit M. ulcerans by bites. In insects, the bacilli were localized exclusively within salivary glands, where it could both multiply contrary to other mycobacteria species. In another experimental study, we report that the crude extracts from aquatic plants stimulate in vitro the growth of M. ulcerans as much as the biofilm formation by M. ulcerans has been observed on aquatic plants. Given that the water bugs are essentially carnivorous, it is difficult to imagine a direct contact in the contamination of aquatic bugs and plants. It seems very likely that an intermediate host exists. In an endemic area of Daloa in Côte d'Ivoire, our observations were confirmed.

[Infectious complications after surgery for hypopharyngeal and laryngeal carcinomas]. / Complications infectieuses après chirurgie carcinologique du pharyngo-larynx.

OBJECTIVE: The objective of this study was to analyze the infectious complications of procedures for carcinoma of the hypopharynx and the larynx to optimize the prevention of septic risks. MATERIAL AND METHODS: This retrospective study included 608 patients who underwent total (n=270) or partial (n=338) laryngectomy between 1984 and 1999. The procedures were performed under rigorous conditions of surgical asepsis and with prolonged antibiotic chemotherapy depending on the type of laryngectomy and past history of external radiotherapy. Twenty factors were studied. Univariate analysis, including 9 factors, and multivariate analysis were performed. RESULTS: The global rate of infectious complications was 11.1%. The percentages of salivary leaks, other wound infections and non-wound infections were respectively 11.9%; 1.5%; 1.5% for total laryngectomy and 1.8%; 2.4%; 3.8% for partial laryngectomy. Statistically significant factors were tumor stage, postoperative hematoma, postoperative lymphorrhea and, to a lesser degree, pharyngeal localization. CONCLUSION: Our rate of infectious complications in oncologic pharyngeal and laryngeal surgery, which is low compared with data in the literature, emphasizes the importance of strict measures of surgical asepsis and prolonged antibiotic chemotherapy as is recommended for so-called contaminated surgery.

[Tracheocele: a rare cause of pharyngeal disorders]. / Trachéocèle: une cause rare de gêne pharyngée.

A 40-year-old woman with an uneventful history consulted for an episode of cervical swelling and pharyngeal disorders with sensation of a foreign body. Cervical and ENT examination was normal. The barium swallow showed a normal esophagus and the CT scan showed an air image in the right side of the trachea. The diagnosis of tracheocele was made at surgery and was confirmed by histology. Clinical, endoscopic, and radiologic outcome was favorable three months after surgical resection of the diverticulum. Tracheocele is rarely reported in the literature. It results from a congenital or acquired weakness of the tracheal wall. The right side is involved more frequently. No specific signs or symptoms have been identified. Diagnosis is often based on CT findings. Surgery confirms the diagnosis and allows resection.

[Hemangiopericytoma of the infratemporalis fossa: a multi-operated patient]. / Hémangiopéricytome de la fosse infra-temporale.

Hemangiopericytoma (HPC) was diagnosed in a 65-year-old man in 1991. Initially the tumor was located in the maxillary sinus. Resection was followed by multiple recurrences involving the infratemporalis fossa (ITF), the nasopharyngeal region, and the right tonsillar region. Over a 10-year-old period, the histology pattern remained unchanged. Multiple approaches, as described in the literature, were used for resection depending on the site of the recurrence. To data, no malignant structure has been identified. Pain and cranial nerve deficits (V2, V3) have been the main squeleae. This case points out the limitations of radical resection because of the difficulty of the approach to this anatomic region. CT scan must be performed to choose the best access route depending on the primary site of the tumor and its extension.

Effect of microbial activity on the mobility of chromium in soils.

The effect of microbial activity on the chemical state of chromium, in a contaminated soil located in the Rhjne-Alpes region (France), has been investigated. This soil contained 4,700 mg kg(-1) Cr, with about 40% present in the soluble hexavalent form. Indigenous microbial activity was found to significantly reduce Cr(VI) to the less mobile form (III) when the soil was incubated at 30 degrees C in an aqueous medium containing glucose and nutrients. A Cr(VI)-reducing strain of Streptomyces thermocarboxydus was isolated from the contaminated soil. The strain was found to metabolize Cr(VI) in a similar manner as an exogenous inoculum of Pseudomonas fluorescens LB300, and to precipitate chromium as a Cr oxyhydroxide with a gammaCrOOH-like local structure. The Cr(VI)-reducing activity of S. thermocarboxydus was induced, or significantly accelerated, by the aggregation of bacterial cells or their adhesion to suspended solid particles, and was stimulated in pure culture by glycerol and chromate.

[Cervical osteophytes and ENT disease: three surgery cases]. / Ostéophytes cervicaux et pathologie du carrefour aéro-digestif.

Vertebral cervical hyperostosis is frequent in the general population but is rarely symptomatic. Dysphagia is the most frequently encountered symptom. We report three cases of cervical hyperostosis leading to ENT symptoms. Two patients had bilateral laryngeal paralysis, rarely described in the literature. These three cases were treated surgically.

Ni clay neoformation on montmorillonite surface.

Polarized extended X-ray absorption fine structure spectroscopy (P-EXAFS) was used to study the sorption mechanism of Ni on the aluminous hydrous silicate montmorillonite at high ionic strength (0.3 M NaClO4), pH 8 and a Ni concentration of 0.66 mM. Highly textured self-supporting clay films were obtained by slowly filtrating a clay suspension after a reaction time of 14 days. P-EXAFS results indicate that sorbed Ni has a Ni clay-like structural environment with the same crystallographic orientation as montmorillonite layers.

Accumulation forms of Zn and Pb in Phaseolus vulgaris in the presence and absence of EDTA.

The internalized speciation of Zn and Pb in roots and leaves of Phaseolus vulgaris grown in zinc sulfate, zinc EDTA, lead nitrate, and lead EDTA solutions were studied by electron microscopy (Zn) and extended X-ray absorption fine structure (EXAFS) spectroscopy (Zn and Pb). Zn was predominantly present as Zn phosphate dihydrate in the roots and leaves of the plant regardless of its form in solution. Pb was predominantly found in the leaves as cerussite (lead carbonate) when the plant was grown in Pb nitrate solution and as a mixture of PbEDTA and an undetermined species in contact with PbEDTA solution. Therefore, Phaseolus vulgaris is able to dissociate totally (Zn) or partly (Pb) the two metal-EDTA complexes from the nutrient solution and to bind these metals in other forms.

[Prognostic value of the number of involved nodes after neck dissection in oropharyngeal and oral cavity carcinoma]. / Valeur pronostique du nombre de ganglions envahis après curage cervical pour carcinome de l'oropharynx et de la cavité buccale.

PURPOSE: To evaluate the relationship between the number of positive nodes and probabilities of locoregional control and survival in patients with invasive squamous cell carcinomas of the oral cavity and oropharynx. MATERIAL AND METHODS: Between 1976 and 1993, we treated with curative intent 183 patients (median age: 56 years; standard deviation: 10 years). Seventy-nine patients (43%) had oropharyngeal primary invasive carcinoma and 104 (57%) had oral cavity (excluding the lip) primary invasive carcinoma. Patients with simultaneous primary lesion or visceral metastases were excluded from the analysis. All the patients had neck dissection with at least six nodes to analyse. One-hundred fifty-nine patients (87%) underwent resection of the primary lesion and 158 (86%) were treated postoperatively with external beam irradiation alone or combined with interstitial implant (median dose: 60 Gy; standard deviation: 10 Gy). Average follow-up was 52 months. RESULTS: The overall 5-year survival rate using the Kaplan-Meier method was 42.6%. The 5-year survival rates were 60.0% when lymph nodes were histologically negative, 39.5% when one lymph node was positive, 28.0% when two lymph nodes were positive and 24.4% when three or more lymph nodes were positive (P = 0.0004). The number of positive nodes did not significantly influence the specific disease-free survival and locoregional control rates. CONCLUSION: Patients with one or more positive neck nodes must have postoperative treatment.

Influence of Anionic Layer Structure of Fe-Oxyhydroxides on the Structure of Cd Surface Complexes.

The nature of crystallographic reactive sites on the lepidocrocite (gammaFeOOH) surface has been determined by atomic force microscopy (AFM) and extended X-ray absorption fine structure (EXAFS) spectroscopy and compared to the surface bonding properties of goethite. To this end, the specific surface areas of lepidocrocite particles, and of their crystal faces, were calculated from the size and shape of individual particles determined by AFM, and the structure of Cd surface complexes was determined from Cd-Fe EXAFS distances. The combined results show that Cd forms solely mononuclear surface complexes, even at 100% surface coverage, and that hydrated Cd octahedra sorb on basal {010} and lateral {hk0}, {h0l} faces of lepidocrocite platelets by sharing edges with surface Fe octahedra. The absence, or scarcity, of corner-sharing linkage between Fe and Cd octahedra on the surface of lepidocrocite is in contrast to goethite (alphaFeOOH), where this type of complex is predominant. The explanation for the observed difference of Cd sorption mechanism on these two polymorphs lies not in the shape and relative surface area of their crystallographic faces, but in their different bulk structures and, specifically, in the stacking mode of anion layers (O(2-), OH(-)) which is hexagonal in alphaFeOOH and cubic in gammaFeOOH. This study demonstrates that the stacking mode of anions in the sorbent solid is a key factor in determining the structure of surface complexes on mineral surfaces. Copyright 2000 Academic Press.

Evidence for the Formation of Trioctahedral Clay upon Sorption of Co(2+) on Quartz.

The sorption mechanism of Co on quartz at room temperature has been investigated by an in-depth analysis of published extended X-ray absorption fine structure (EXAFS) spectroscopy and solution chemistry data. In particular, the 3.5-5 Å mid-range atomic environment of Co has been determined with unprecedented precision by combining ad initio FEFF7.02 calculations and results obtained by polarized EXAFS on the mid-distance structure of sheet silicate minerals. The local atomic environment around sorbed Co atoms is identical to that of Co in trioctahedral clays and substantially different from that in the cobalt hydroxide Co(OH)(2(s)). Neoformation of a trioctahedral clay is consistent with calculated thermodynamic solubilities, which indicate that 2:1 and 1:1 Co-rich hydrous silicates, similar to kerolite and chrysotile, are less soluble than Co(OH)(2(s)). Consequently, precipitation of Co-rich clay is favored over that of Co(OH)(2(s)) at pH values below 9 and for a dissolved Si concentration equal to quartz solubility. New experimental data show that dissolved Si concentrations can approach, and even exceed, that of quartz solubility during the short times of sorption experiments. Based on the available data, it is not possible to conclude unequivocally if the Co layer silicate grew epitaxially on the quartz surface, topotactically in a surface amorphous layer, or independently of the quartz framework structure. The structural and chemical interpretation is supported by recent published studies in which sorption of a hydrolyzable cation leads to the neoformation of a mixed layer phase formed from the sorbate species and the sorbent metal. This surface-induced precipitation mechanism is a general phenomenon that may account for the formation of secondary clays as coatings on silicates. Copyright 1999 Academic Press.

Sorption of Metal Ions on Clay Minerals.

The mechanism of Co uptake from aqueous solution onto hectorite (a magnesian smectite) and its impact on the stability of this clay mineral were investigated as a function of Co concentration (TotCo = 20 to 200 µM, 0.3 M NaNO(3)) and ionic strength (0.3 and 0.01 M NaNO(3), TotCo = 100 µM) by combining kinetics measurements and Co K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy. The morphology of the sorbent phase was characterized by atomic force microscopy (AFM) and consists of lath-type particles bounded by large basal planes and layer edges. At low ionic strength (0.01 M NaNO(3)), important Co uptake occurred within the first 5 min of reaction, consistent with Co adsorption on exchange sites of hectorite basal planes. Thereafter, the sorption rate dramatically decreased. In contrast, at high ionic strength (0.3 M NaNO(3)), Co uptake rate was much slower within the first 5 min and afterward higher than at 0.01 M NaNO(3), consistent with Co adsorption on specific surface sites located on the edges of hectorite. Time-dependent isotherms for Co uptake at high ionic strength indicated the existence of several sorption mechanisms having distinct equilibration times. The dissolution of hectorite was monitored before and after Co addition. A congruent dissolution regime was observed prior to Co addition. Just after Co addition, an excess release of Mg relatively to congruent dissolution rates occurred at both high and low ionic strengths. At high ionic strength, this excess release nearly equaled the amount of sorbed Co. The dissolution rate of hectorite then decreased at longer Co sorption times. EXAFS spectra of hectorite reacted with Co at high and low ionic strengths and for reaction times longer than 6 h, exhibited similar features, suggesting that the local structural environments of Co atoms are similar. Spectral simulations revealed the occurrence of approximately 2 Mg and approximately 2 Si neighboring cations at interatomic distances characteristic of edge-sharing linkages between Co and Mg octahedra and corner-sharing linkages between Co octahedra and Si tetrahedra, respectively. This local structure is characteristic of inner sphere mononuclear surface complexes at layer edges of hectorite platelets. The occurrence of these complexes even at low ionic strength apparently conflicts with kinetics results, as exchangeable divalent cations are known to form outer sphere surface complexes. To clarify this issue, the amount of Co adsorbed on exchange sites was calculated from the solute Co concentration, assuming that cation exchange was always at equilibrium. These calculations showed that sorbed Co was transferred within 48 h from exchange sites to edge sorption sites. Copyright 1999 Academic Press.

[Otosclerosis surgery: a series of 227 cases. Introduction of CO2 laser]. / Chirurgie de l'otospongiose. A propos de 227 cas introduction de la platinotomie laser CO2.

OBJECTIVES: To evaluate the effects of the size of the footplate opening on the hearing results in surgical treatment of otosclerosis and the use of CO2 laser in this indication. PATIENTS AND METHODS: 190 patients with otosclerosis underwent 227 procedures between 1986 and 1995. Hearing results and symptoms were analyzed to compare the different procedures: 140 stapedectomies, 87 Fisch's stapedotomies, 35 of them with manual perforator, 52 of them with CO2 laser. RESULTS: Air/bone gap closure within 10 dB was obtained in 87, 92 and 97 percent of stapedectomies and in 80, 84 et 90 percent of stapedotomies after 3 months, 1 and 3 years (NS). Bone conduction was improved in 81, 80 et 63 percent of stapedectomies and 87, 97, 60 percent of stapedotomies after the same time (NS). Air/bone gap closure within 10 dB was obtained in 75 and 80 percent of manual perforator stapedotomies and in 84 and 88 percent of CO2 laser stapedotomies after 3 months, and 1 year (NS). Bone conduction was improved in 78 and 96 percent of manual perforator stapedotomies and 95 and 100 percent of CO2 laser stapedotomies after the same time (NS). No facial palsy or prolonged vertigo occurred. There was one case of anucusis following a stapedectomy. CONCLUSION: Although both stapedectomy and stapedotomy produced equivalent air/bone gap closure, reduction of inner ear trauma was noted with Fisch's stapedotomy. CO2 laser technique is a safe procedure, which optimizes the Fisch's stapedotomy.

Sorption of Metal Ions on Clay Minerals.

The local structural environment of Co sorbed on hectorite (a magnesian smectite) has been investigated by polarized EXAFS (P-EXAFS) spectroscopy on a self-supporting film of Co-sorbed hectorite. This sorption sample was prepared by contacting Co and hectorite at pH 6.5 and at high ionic strength (0.3 M NaNO3) to favor pH-dependent sorption reaction over cation exchange. A self-supporting film was elaborated after 120 h of reacting time, when apparent quasi-equilibrium conditions were attained. The half-width at half maximum of the orientation distribution of c* axis of individual clay platelets off the film normal was determined by quantitative texture analysis, and found to be equal to 18.9 degrees. Co K-edge P-EXAFS spectra were recorded at angles between the incident beam and the film normal equal to 0 degrees, 35 degrees, 50 degrees, and 60 degrees; the 90 degrees spectrum was obtained by extrapolation. Spectral analysis led to the identification of the two nearest cationic subshells containing 1.6 +/- 0.4 Mg at 3.03 Å and 2.2 +/- 0.5 Si at 3.27 Å. These distances are respectively characteristic of edge-sharing linkages between Mg and Co octahedra and of corner-sharing linkages between Co octahedra and Si tetrahedra, as in clay structures. The angular dependence of the Co-Mg and Co-Si contributions indicates that Co-Mg pairs are oriented parallel to the film plane, whereas Co-Si pairs are not. These results are interpreted by the formation of Co inner-sphere mononuclear surface complexes located at the edges of hectorite platelets, in the continuity of the (Mg, Li) octahedral sheet. Copyright 1999 Academic Press.

[Necessity of auditory and academic supervision in patients with unilateral hearing disorder. Retrospective study of 175 children]. / Nécessité d'un suivi audiologique et scolaire de l'enfant sourd unilatéral. Etude rétrospective de 175 enfants.

This report reviews a consecutive series of 175 children suffering from unilateral hearing loss of 20 dB or more evaluated at the Clocheville Hospital between 1980-1991. We found no numerical preponderance of gender nor of side impairment. The mean age of diagnosis was 6.9 years. Based on speech frequency threshold averages, the loss was profound in 49.7%. 32.8% of the children experienced a deterioration of hearing of 10 dB or more. 40.4% of the children had repeated a grade during primary school (versus 16.3% in normal hearing population, p < 0.001). Monaural deafness especially when more than 40 dB, or delayed identification is significantly associated with a grade failure. A concerted effort aimed at early identification and management strategies in cases of unilateral hearing loss in children is warranted.