Human pentastomiasis in Sub-Saharan Africa.

Pentastomiasis is a rare zoonotic infection but it is frequently observed in Africa and Asia. Most human infections are caused by members of the Armillifer armillatus species. They are responsible for visceral pentastomiasis in Western and Central Africa. Humans may be infected by eating infected undercooked snake meat or by direct contact with an infected reptile. An increasing number of infections are being reported in Congo, Nigeria, and Cameroon. Despite an occasionally high number of nymphs observed in human viscera, most infections are asymptomatic and often diagnosed by accident during surgery or autopsy. The clinical presentation of pentastomiasis is quite varied and depends on infected tissues. The liver, lungs, and pleura are most frequently involved. Abdominal emergencies have been reported. Diagnostic delays always occur and diagnosis focuses on the patient's lifestyle and living environment. It is mainly based on the morphological description of the parasite's calcified cuticle, the site of the lesion, and the parasite's region of origin. Most patients do not require any treatment. Personal measures such as avoidance of contact with snake droppings are recommended to prevent transmission. Imported pentastomiasis has been observed in African migrants.

[Vesicular contact dermatitis due to Paederus in Cameroon and review of the literature]. / Dermatite vésicante à Paederus au Cameroun et revue de littérature.

This irritant blister dermatitis is caused by the genus Paederus whose geographical distribution is worldwide, with a higher incidence in tropical areas. It is induced by direct skin contact with pederin, a blistering and caustic substance found in the abdomen (coelome) of Paederus insects (insect order Coleoptera: family Staphylinidae). The diagnosis is based on the presence of typical clinical features combined with compatible epidemiological features. Our goal is to describe the epidemiological and clinical features of this irritant contact dermatitis in Cameroon through a retrospective study conducted at the end of the rainy season at the Oku Hospital in Northwest Cameroon and to also include cases reported at the medical center of the French Embassy in Yaounde during this same timeframe. In addition, we conducted a literature review of paederus dermatitis. Nineteen patients were included in this study. More than half of the patients presented with more than two lesions predominantly localized to the face or the neck; less than half had complications manifesting as either localized or respiratory reactions and three patients presented periorbital involvement. This study confirms the presence of paederus dermatitis in Cameroon. It is mainly localized in the unusual geoclimatic region of the western high mountains within the country, as well as the usual warm, moist areas of Yaounde. The clinical evolution of this dermatitis is usually one of spontaneous and uneventful resolution with complications being rare. Curative treatment is one of localized topical therapies while oral antibiotic therapy should be reserved for more complicated cases.

Na4.25Mo15S19: a novel ternary reduced molybdenum sulfide containing Mo6 and Mo9 clusters.

The structure of tetra-sodium penta-deca-molybdenum nona-deca-sulfide, Na4.25Mo15S19, is isotypic with Na3.9Mo15Se19 [Salloum et al. (2013 ▶). Acta Cryst. E69, i67-i68]. It is characterized by Mo6S (i) 8S (a) 6 and Mo9S (i) 11S (a) 6 (where i represents inner and a apical atoms) cluster units that are present in a 1:1 ratio. The cluster units are centered at Wyckoff positions 2b and 2c, and have point-group symmetry -3 and -6, respectively. The clusters are inter-connected through additional Mo-S bonds. The Na(+) cations occupy inter-unit voids formed by six or seven S atoms. One Mo, one S and one Na site [occupancy 0.751 (12)] are situated on mirror planes, and two other S atoms and one Na site (full occupancy) are situated on threefold rotation axes.

Ag(2.54)Tl(2)Mo(12)Se(15): a new structure type containing Mo(6) and Mo(9) clusters.

The novel structure-type Ag(2.54)Tl(2)Mo(12)Se(15) (silver thallium molybdenum selenide) is built up of Mo(6)Se(i)(8)Se(a)(6) and Mo(9)Se(i)(11)Se(a)(6) cluster units in a 1:2 ratio, which are three-dimensionally connected to form the Mo-Se network. The Ag and Tl cations are distributed in several voids within the cluster network. Three of the seven independent Se atoms and one Tl atom lie on sites with 3.. symmetry (Wyckoff sites 2c or 2d).

Synthesis, crystal structures, and physical properties of the novel Ca(x)R(17-x)Mo19O46 (4 < or = x < or = 7; R = Ce, Pr, Sm, and Gd) compounds containing centered Mo19 nu2-octahedral clusters.

The novel quaternary reduced molybdenum oxides Ca(x)R(17-x)Mo(19)O(46) (4 < or = x < or = 7; R = Ce, Pr, Sm, and Gd) have been synthesized by a solid-state reaction at 1400 degrees C for 48 h in sealed molybdenum crucibles. The crystal structure was determined on a single crystal of Ca(5.24)R(11.76)Mo(19)O(46) by X-ray diffraction. This compound crystallizes in the monoclinic space group C2/m: a = 19.5192(4) A, b = 11.1244(3) A, c = 13.2589(5) A, beta = 132.055(1) degrees, V = 2137.7(1) A(3), Z = 2. Refinements yield R1(F(2)) = 0.0388 and wR2(F(2)) = 0.0792 for 5667 unique reflections. The structure is built up from alternating slabs made up of Mo forming centered Mo(19) nu(2)-octahedral clusters, Ca, Pr, and O atoms and slabs containing only Ca, Pr, and O atoms. The Mo(19) cluster, in which the Mo-Mo distances range from 2.7274(4) to 2.7940(7) A, results from a three-dimensional condensation of six Mo(6) octahedra. The Ca(2+) and Pr(3+) cations occupy seven crystallographically independent sites with coordination numbers in the O atoms varying from 6 to 8. Magnetic susceptibility measurements made on the Ca(x)Pr(17-x)Mo(19)O(46) (x = 4-7) compounds confirm the presence of Pr(3+) cations, and no magnetic ordering was observed down to 4.2 K. Electrical resistivity measurements on a single crystal of Ca(approximately 5)Pr(approximately 12)Mo(19)O(46) show a semiconducting behavior.

The disordered cluster compound CaMo5(Mo0.38Ti0.62)O10.

The title compound, calcium pentamolybdenum titanium decaoxide, is isomorphous with the AMo(5)(Ti(0.7)Mo(0.3))O(10) (A = Sr and Eu) compounds. The smaller size of calcium induces a higher molybdenum content on the capping sites of the bioctahedral Mo(10) clusters, leading to more Mo(11) and Mo(12) clusters in the crystal structure. The oxygen framework derives from the stacking of close-packed layers along the a direction in the ...ABAC... sequence. The Ca(2+) ions occupy large cavities which result from the fusion of two cubooctahedra and are surrounded by ten O atoms. The Ti(4+) ion is octahedrally coordinated by the O atoms.

The pyrochlore-type molybdate Pr(1.37)Ca(0.63)Mo(2)O(7).

Praseodymium calcium dimolybdenum hepta-oxide, Pr(1.37)Ca(0.63)Mo(2)O(7), crystallizes in the cubic pyrochlore-type structure. In the crystal structure, MoO(6) octa-hedra are linked together by common corners, forming a three-dimensional [Mo(2)O(6)] network. The Pr and Ca atoms and the remaining O atoms are located in the voids of the [Mo(2)O(6)] network. The Pr and Ca atoms are distributed statistically over the same 16c crystallographic position with site-occupancy factors of 0.684 (3) and 0.316 (3), respectively. They are surrounded by eight O atoms forming a ditrigonal scalenohedron. All atoms lie on special positions. The (Pr, Ca) and Mo atoms are, respectively in the 16c and 16d positions with m symmetry, and the O atoms in the 48f or 8a positions with mm or 3m site symmetry, respectively.

Rare-earth site splitting in Sm3MoO7.

Trisamarium molybdenum heptaoxide, Sm(3)MoO(7), is isomorphous with Ln(3)MoO(7) (Ln = La and Pr). The crystal structure consists of chains of corner-linked MoO(6) octahedra running parallel to the b axis and separated from each other by seven- or eight-coordinate Sm-O polyhedra. In contrast to La(3)MoO(7) and Pr(3)MoO(7), a splitting of one Sm site into two positions is observed.

Phylogeography and population genetics of the maize stalk borer Busseola fusca (Lepidoptera, Noctuidae) in sub-Saharan Africa.

The population genetics and phylogeography of African phytophagous insects have received little attention. Some, such as the maize stalk borer Busseola fusca, display significant geographic differences in ecological preferences that may be congruent with patterns of molecular variation. To test this, we collected 307 individuals of this species from maize and cultivated sorghum at 52 localities in West, Central and East Africa during the growing season. For all collected individuals, we sequenced a fragment of the mitochondrial cytochrome b. We tested hypotheses concerning the history and demographic structure of this species. Phylogenetic analyses and nested clade phylogeographic analyses (NCPA) separated the populations into three mitochondrial clades, one from West Africa, and two--Kenya I and Kenya II--from East and Central Africa. The similar nucleotide divergence between clades and nucleotide diversity within clades suggest that they became isolated at about the same time in three different refuges in sub-Saharan Africa and have similar demographic histories. The results of mismatch distribution analyses were consistent with the demographic expansion of these clades. Analysis of molecular variance (amova) indicated a high level of geographic differentiation at different hierarchical levels. NCPA suggested that the observed distribution of haplotypes at several hierarchical levels within the three major clades is best accounted for by restricted gene flow with isolation by distance. The domestication of sorghum and the introduction of maize in Africa had no visible effect on the geographic patterns observed in the B. fusca mitochondrial genome.

La5Mo6O21: a novel ternary reduced molybdenum oxide containing {MoIV}3 clusters and isolated MoV centres.

The crystal structure of La5Mo6O21 (pentalanthanum hexamolybdenum henicosaoxide) is made up of Mo3O13 units containing triangular {MoIV}3 clusters, three distorted MoVO6 octahedral units and six interstitial LaIII atoms. The Mo3O13 unit consists of three edge-sharing MoIVO6 units involving Mo-Mo bonding. The three MoVO6 octahedra share their corners or edges with each other and with the Mo3O13 units.

Use of ITS rDNA for discriminating of larval stages of two microphallid (Digenea) species using Hydrobia ulvae (Pennant, 1777) and Corophium volutator (Pallas, 1766) as intermediate hosts.

Digenean trematodes encompass several species with little morphological differentiation in the larval stages and, as a result, uncertainty prevails regarding species identification. The microphallid trematode Maritrema subdolum occurs widespread geographically in mud snail and crustacean hosts in European marine shallow-water ecosystems. Larval stages of this and other congeneric species are, however, difficult to separate morphologically. To verify the species status and to secure identification of two co-occurring microphallids, M. subdolum and microphallid sp. no. 15 (Deblock, 1980), we examined the nucleotide sequences of the internal transcribed spacer regions (ITS1, ITS2). From fragments consisting of both ITS regions and the 5.8S gene (nearly 1,200 bp), a sequence divergence of 2.9% between the two types was recorded. In accordance with the morphological traits of the cercariae (stylet shape, length), the results support the view that the two types actually represent different species. Species-specific primers were prepared for each species. They proved to be efficient diagnostic tools for identifying single larval-stage individuals. Using these primers, infections in host organisms were also verified without performing a dissection of the host individuals.

Structural trends and the electronic structure of the rare-earth oxomolybdates RMo(5)O(8) (R = La, Ce, Pr, Nd, Sm, Eu and Gd) containing chains of bioctahedral Mo(10) clusters.

The crystal structures of the rare-earth members of the series RMo(5)O(8) (R = Ce to Eu) have been investigated and compared with those of the La and Gd members previously published in order to understand the influences of the size and the charge of the cation on the different Mo-Mo bonds. The RMo(5)O(8) compounds crystallize in the monoclinic space group P2(1)/c. Their crystal structure is characterized by bioctahedral Mo(10) clusters forming extended chains. The results of our single-crystal studies show that the modification of charge predominantly affects the Mo-Mo bonds between the Mo(10) clusters and, to a lesser extent, the intra-cluster distances, while the cationic size induces only small variations. Theoretical investigations confirm this statement and allow the understanding of the bonding mode in these compounds.

Synthesis, structural trends, and physical and electronic properties of the reduced molybdenum oxides R(4)Mo(4)O(11) (R = Nd-Tm and Y) containing infinite chains of trans-edge-shared octahedral clusters.

The new compounds R(4)Mo(4)O(11) (R = Y, Nd, Sm-Tm) have been synthesized as crystalline powders by solid-state reaction in a sealed molybdenum crucible at 1400 degrees C. Single crystals suitable for X-ray structure determinations and resistivity measurements were also prepared. The R(4)Mo(4)O(11) compounds crystallize in the orthorhombic space group Pbam with four formulas per unit cell. The crystal structure of these compounds is based on infinite chains of trans-edge-shared molybdenum octahedra, which are widely separated by the rare-earth cations that are in monocapped trigonal prismatic coordination of oxygen atoms. Consequently, adjacent metallic chains do not share oxygen atoms and the shortest interchain Mo-Mo distance is greater than 7 A. Within the infinite chains, a strong pairing between the apical Mo atoms occurs, leading to a pattern of alternating short and long distances between these atoms. Resistivity measurements on single crystals show that the R(4)Mo(4)O(11) compounds are small band gap semiconductors, and magnetic susceptibility studies are in agreement with the presence of R(3+) ions. In addition, antiferromagnetic orderings have also been observed for the R(4)Mo(4)O(11) compounds with R = Gd-Tm below 5 K. Theoretical calculations confirm the stabilization of the structure by the distortion and agree with the resistivity and magnetic measurements.

Relationship of folate to colorectal and cervical cancer: review and recommendations for practitioners.

Evidence suggests that folate may play a role in cancer prevention. A plausible mechanism for prevention lies in the integral role that folate plays in deoxyribonucleic acid (DNA) synthesis and methylation. DNA methylation most likely regulates gene expression. Abnormal methylation, specifically hypomethylation, has been associated with tumorigenesis. The availability of methyl groups needed for adequate DNA methylation may be negatively influenced by low folate status, alcohol intake, or genetic polymorphisms that affect folate metabolism. Observational studies evaluating the association between folate and risk for colorectal and cervical cancers or precancerous conditions have produced conflicting results, and clinical trial data are needed to confirm a cause-and-effect relationship. However, several studies show interesting associations between cancer risk and factors that influence methyl group availability. Although data relating folate to cancer risk remain equivocal, when coupled with the other potential health benefits associated with folate, evidence supports recommending that people consume folate-rich foods such as fruits and vegetables. People consuming alcohol on a daily basis may especially benefit from additional folate in their diets.

Role of fibrates and HMG-CoA reductase inhibitors in gallstone formation: epidemiological study in an unselected population.

Fibrate derivatives and HMG-CoA reductase inhibitors modify homeostasis of cholesterol. The aim of this study was to assess in an unselected population whether these hypolipidemic drugs are risk factors for cholelithiasis or, conversely, are protective agents. Both sexes, all socioeconomic categories, pregnant women, and cholecystectomized subjects were included. Clinical data collection and gallbladder ultrasonography were both carried out in a double-blind fashion. Fibrate derivatives were predominantly fenofibrate, HMG-CoA reductase inhibitors were simvastatin and pravastatin. On univariate analysis, age (>50 years), sex, and use of fibrates were found to be significantly related to the presence of cholelithiasis. Age, sex, and fibrate treatment remained independently correlated with the presence of gallstones on multivariate analysis. With fibrates, the relative risk for lithiasis was 1.7 (P = 0.04). The HMG-CoA reductase inhibitors were not associated with a protective effect on univariate analysis. Of the lipid-lowering drugs, only fibrate derivatives were found to increase the risk of gallstone formation.

Total artificial nutrition is associated with major changes in the fecal flora.

BACKGROUND: Animal studies have demonstrated dramatic changes in the intestinal flora during total enteral (TEN) or parenteral (TPN) nutrition. AIM OF THE STUDY: To assess the impact of TEN and TPN on human intestinal microflora. METHODS: Eight patients on fiber-free TEN, five patients on TPN, and ten controls were studied. Fecal bacteria were identified and numbered (logCFU/g feces), and fecal short-chain fatty acids (SCFAs) were measured in stool samples, by gas-liquid chromatography. RESULTS: In TEN patients, compared to controls (P < 0.01), aerobes were increased (8.46 +/- 0.24) while anaerobes were decreased (5.79 +/- 0.84). In TPN patients, both aerobes and anaerobes were decreased compared to controls (5.64 +/- 0.27 and 5.31 +/- 1.09 respectively, P < 0.01). Total SCFAs were lower in TPN patients than in TEN patients (48.3 +/- 16.6 vs 118.6 +/- 24.1 mmol/kg, P < 0.05). CONCLUSIONS: Both TPN and TEN induce modifications in the intestinal microflora. During TPN, a homogeneous decrease occurs in both aerobic and anaerobic bacteria. TEN decreases only anaerobic bacteria, while aerobic bacteria are increased. This imbalance may play a role in the pathophysiology of TEN-induced diarrhea.

[So-called spontaneous intramural dissection of the esophagus]. / Dissection intramurale dite "spontanée" de l'oesophage.

We report two cases of spontaneous esophageal intramural dissection in two women aged 65 and 79 years. Initial symptoms were a constrictive retrosternal thoracic pain during a meal. Minor hematemesis accompanied by dysphagia or odynophagia appeared during the following hours. After excluding a cardiovascular emergency, diagnosis was confirmed by upper GI endoscopy that found a large mucosal longitudinal dissection; the lesion extended from mid-esophagus until short above the gastro-esophageal junction. Intramural parietal dissection characteristically appeared on barium swallow as a "double-barrelled" esophagus related to a thin radiolucent mucosal membrane separating the false and true lumens. Medical treatment with total parenteral nutrition, intravenous gastric antisecretory drugs, antibiotics in 1 patient was continued until symptoms disappeared; oral feeding was then started without incident. Follow-up endoscopic examinations confirmed complete healing. Regardless of etiology which remains speculative, spontaneous intramural dissection of the esophagus probably results from an intramural hematoma in most cases.

The role of endoscopic retrograde cholangiopancreatography in the management of hepatic hydatid disease.

BACKGROUND AND STUDY AIMS: Hydatid disease of the liver, and its complications, causes serious morbidity and mortality. We evaluated the role of endoscopic retrograde cholangiopancreatography (ERCP) in the management of hepatic hydatid disease. PATIENTS AND METHODS: This retrospective analysis includes 28 patients with hepatic hydatid disease who underwent ERCP. ERCP was performed preoperatively in 11 patients, for acute cholangitis (n =7), acute pancreatitis (n = 1) and right upper quadrant pain (n = 3), and in eight asymptomatic cases to search for fistulae between the cyst and the biliary tree. In a further nine patients ERCP was performed for early (< 30 days; n = 7) and late (n = 2) postoperative biliopancreatic problems. RESULTS: In all seven patients with cholangitis preoperative ERCP with EST and ductal clearance of daughter cysts and debris led to substantial clinical improvement, including four acutely ill elderly patients who stabilized and were later able to undergo surgery. EST in two of the three patients with pain who had papillary stenosis led to resolution of the abdominal pain. Six of the seven postoperative fistulae could be successfully treated endoscopically using EST. CONCLUSIONS: This study demonstrates the usefulness of ERCP in symptomatic patients with hepatic hydatid cysts; EST enables clearance of the common bile duct and allows healing of postoperative fistulae in the majority of patients. We do not, however, recommend performing routine preoperative ERCP in asymptomatic patients with the disease.