Synthesis and properties of europium-based phosphors on the nanometer scale: Eu2O3, Gd2O3:Eu, and Y2O3:Eu

Nanocrystals of oxides containing europium as the main constituent or as a doping element in RE2O3 ( RE=Y, Gd) have been prepared by direct oxide precipitation in high-boiling polyalcohol solutions and characterized by high-resolution TEM, absorption spectroscopy, and luminescence spectroscopy. The samples obtained consisted of concentrated and colloidally stable suspensions of luminescent oxide nanoparticles with an average grain diameter in the range 2-5 nm. The nanoparticles were found to be highly crystalline despite their ultrasmall size and the low temperature of 180 degrees C applied during the synthesis. Upon UV excitation, the red luminescence relative to the 5D0-->7Fn transition within the cubic form of RE2O3 exhibits some important differences from that usually found in bulk materials.

[Surgical treatment of acute pancreatitic with infected necrosis by necrosectomy-pancreatostomy]

Technical modalities of surgical treatment of infected pancreatic necrosis remains controversial. The aim of this retrospective study was to assess the results of necrosectomy associated by pancreatostomy using active drainage according Mikulicz, which is currently an unusual technique.

PATIENTS AND METHODS

From 1985 to 1997, 18 consecutive patients (median age = 63; range = 35-88 years) were operated on through laparotomy for infected necrosis and treated by necrosectomy combined with Mikulicz drainage. Fourteen patients were referred from another center, including 9 who had previous surgery. Necrosectomy was performed after a median delay of 22 days (1-45) after onset of pancreatitis, in all patients because of severe sepsis (including 12 patients with persisting shock) and presence at CT scan of necrotic collections containing gas bubbles (n = 15) and/or infection proven by percutaneous aspiration (n = 3).

RESULTS

After the first procedure, patients underwent between 2 and 25 (median: 5) additional necrosectomies through the pancreatostomy tract. Thirteen surgical complications were observed in 8 patients: digestive fistula (n = 7), intraabdominal bleeding (n = 3), gastrointestinal haemorrhage (n = 1), colic stenosis with colectasy (n = 1). Five patients, all referred from another center, died (28%) between the 47th and the 140th day from multiorgan failure (n = 4) or gastrointestinal haemorrhage (n = 1). The median hospital stay was 109 days (26-265) including 51 in intensive care unit (1-134). The 13 surviving patients were followed during an average of 2 years (4 months-7 years). All developed an incisional hernia of the pancreatostomy tract, which was surgically treated in 6 cases.

CONCLUSIONS

Necrosectomy-pancreatostomy is an appropriate treatment of acute pancreatitis with infected necrosis, despite the usual need of additional but easy necrosectomies, and the frequent occurrence of incisional hernia. Results observed in patients referred to our center suggest that earlier diagnosis of necrosis infection using percutaneous aspiration could improve the prognosis.

[Oriental biliary lithiasis. Retrospective study of 690 patients treated surgically over 8 years at Hospital 108 in Hanoi (Vietnam)]

The purpose of this study was to review the unique features distinguishing Oriental from Western gallbladder disease based on a series of 690 patient who underwent surgical treatment at hospital 108 in Hanoi. Oriental cholangiohepatitis often affects in young patients with no gender predilection. The disease originates mainly in canaliculi and leads to blockage or obstruction of the main bile duct inside and outside the liver. Onset has been related to nutritional, infectious, and parasitic factors. Ascariasis may play a determinant role. Because of these unique features, surgical treatment is usually focused on the main bile duct and depends on the size, number, and effects of gallstones. The authors recall that excision of liver tissue may be unavoidable in some cases due to the severity and consequences of lithiasis.

[Kidney cancer in horseshoe kidney. A case report of an unexpected diagnosis]

The authors report a case of renal cell carcinoma in a horseshoe kidney and discuss diagnostic and therapeutical aspects arising from this combination. Renal carcinoid tumors and nephroblastoma seems to be more frequent in this malformation. Diagnosis of horseshoe kidney may be difficult and angiography examination is very useful to confirm renal anomaly, tumor situation, and to plan the surgical approach because vascularization vary case to case. Heminephrectomy adapted to neoplasic localisation remains the essential treatment.

A cluster of four D7-related genes is expressed in the salivary glands of the African malaria vector Anopheles gambiae

Four genes expressed in the Anopheles gambiae adult female salivary glands and similar in sequence to the Aedes aegypti D7 gene were identified. The genes, called D7-related (D7r), are included in a single cluster encompassing approximately six kilobases on chromosome arm 3R. The deduced proteins contain secretory signals and they are probably injected by the mosquito into the host with the saliva during blood feeding. The region of similarity to D7 encompasses the carboxy-terminal part of the Ae. aegypti protein and the different An. gambiae D7r show a degree of similarity to each other, varying from 53% to 73%. The weak but significant similarity to members of a wide family of insect proteins, including odourant- and pheromone-binding proteins, raises the possibility that the D7r-encoded proteins may bind and/or carry small hydrophobic ligands.

Developmental variation in epidermal growth factor receptor size and localization in the malaria mosquito, Anopheles gambiae

The AGER gene encoding the epidermal growth factor receptor (EGFR) of the malaria mosquito Anopheles gambiae was cloned and sequenced. It represents a canonical member of this family of tyrosine kinase proteins exhibiting many similarities to orthologues from other species, both on the level of genomic organization and protein structure. The mRNA can be detected throughout development. Western analysis with an antibody raised against the extracellular domain of the mosquito protein suggests developmental variation in protein size and location that may be involved in the function of EGFR in the mosquito.

[Value of the bilio-intestinal bypass in biliary disease in the Far East: retrospective study of 5 year experience at the Calmette Hospital of Phnom Penh (Cambodia)]

Gallstone disease in the Far East exhibits a number of special features regarding epidemiology and etiology as well as indications for and response to surgical treatment. Surgical bypass techniques seldom used for treatment of gallstone disease in the West can be highly effective in lowering complication and recurrence rates in oriental patients. The purpose of this retrospective report is to describe a 5-year experience with gallstone disease at the Calmette Hospital in Phnom Penh (Kingdom of Cambodia). After reviewing the main pathological features encountered, we describe the indications for the two bypass techniques used. Choledocoduodenostomy was used for frail, elderly patients while choledochojejunostomy was the treatment of choice and achieved excellent short, middle, and long-term results in younger patients.

Beta-integrin of Anopheles gambiae: mRNA cloning and analysis of structure and expression

We have isolated an mRNA encoding a beta integrin subunit of the malaria mosquito Anopheles gambiae. Our analysis predicts a protein that is very similar to betaPS, the fruitfly orthologue. The gene is expressed during all developmental stages and it is found in all body parts, including the midgut. Finally, the expression of the gene does not seem to be modulated during blood meals, except for a substantial increase 48 h posthaematophagy, when digestion is nearly complete.

From first base: the sequence of the tip of the X chromosome of Drosophila melanogaster, a comparison of two sequencing strategies

We present the sequence of a contiguous 2.63 Mb of DNA extending from the tip of the X chromosome of Drosophila melanogaster. Within this sequence, we predict 277 protein coding genes, of which 94 had been sequenced already in the course of studying the biology of their gene products, and examples of 12 different transposable elements. We show that an interval between bands 3A2 and 3C2, believed in the 1970s to show a correlation between the number of bands on the polytene chromosomes and the 20 genes identified by conventional genetics, is predicted to contain 45 genes from its DNA sequence. We have determined the insertion sites of P-elements from 111 mutant lines, about half of which are in a position likely to affect the expression of novel predicted genes, thus representing a resource for subsequent functional genomic analysis. We compare the European Drosophila Genome Project sequence with the corresponding part of the independently assembled and annotated Joint Sequence determined through "shotgun" sequencing. Discounting differences in the distribution of known transposable elements between the strains sequenced in the two projects, we detected three major sequence differences, two of which are probably explained by errors in assembly; the origin of the third major difference is unclear. In addition there are eight sequence gaps within the Joint Sequence. At least six of these eight gaps are likely to be sites of transposable elements; the other two are complex. Of the 275 genes in common to both projects, 60% are identical within 1% of their predicted amino-acid sequence and 31% show minor differences such as in choice of translation initiation or termination codons; the remaining 9% show major differences in interpretation.

Anopheles gambiae laminin interacts with the P25 surface protein of Plasmodium berghei ookinetes

Laminin is a major constituent of the basal lamina surrounding the midgut of the malaria vectors that has been implicated in the development of the Plasmodium oocyst. In this report we describe the cloning of the Anopheles gambiae gene encoding the laminin gamma 1 polypeptide and follow its expression during mosquito development. To further investigate the putative role of laminin in the transmission of the malaria parasite we studied the potential binding of the P25 surface protein of Plasmodium berghei using a yeast two-hybrid system. Heterodimer formation was observed and does not require any additional protein factors since purified fusion proteins can also bind each other in vitro. Laminin gamma 1 also interacts with the paralogue of P25, namely P28, albeit more weakly, possibly explaining why the two parasite proteins can substitute for each other in deletion mutants. This represents the first direct evidence for molecular interactions between a surface protein of the Plasmodium parasite with an Anopheles protein; the strong interplay between laminin gamma 1 and P25 suggests that this pair of proteins may function as a receptor/ligand complex regulating parasite development in the mosquito vector.

Molecular characterization of ribosomal DNA polymorphisms discriminating among chromosomal forms of Anopheles gambiae s.s

The sequence of a 2.3 kb long DNA segment derived from the 5'-most end of the ribosomal intergenic spacer was determined in three chromosomal forms of Anopheles gambiae s.s. The analysis revealed that the sequence of the Mopti form differed from that of the Bamako and Savanna forms by a total of ten nucleotide substitutions. Using these sequence variations we set up a diagnostic polymerase chain reaction (PCR) assay to distinguish mosquitoes belonging to the three chromosomal forms, facilitating studies on the distribution and the ecology of these incipient taxa. The assay also allows to distinguish whether a given specimen could represent a heterozygote between Mopti and Savanna or Bamako.

Genetic homogeneity of the urofacial (Ochoa) syndrome confirmed in a new French family

The urofacial syndrome (UFS) or Ochoa syndrome has been reported as a rare autosomal recessive disorder comprising a uropathy and facial abnormalities. The gene was mapped on chromosome region 10q23-q24. We report the first European cases of UFS. Haplotype analyses in our French family were compared with those previously described in patients from Columbia and America (literature data). The results are compatible with the same localization of the critical region and favor the hypothesis of genetic homogeneity.

Distinct roles for pbs21 and pbs25 in the in vitro ookinete to oocyst transformation of Plasmodium berghei

We have developed an in vitro culture system for early sporogonic stages of Plasmodium berghei, which can be used to study developmental events normally taking place in the midgut of an infected mosquito. These include penetration of insect cells by the mature ookinete, transformation into oocysts and the early development of the latter, sustained through several rounds of nuclear division. The system, based upon co-culture of enriched ookinetes with several established insect cell lines, was used to study the development of mutant ookinetes lacking both the Pbs21 and Pbs25 surface proteins. Motility and entry of double knockout and Pbs21 single knockout ookinetes into the insect cells are normal, but the number of ookinetes successfully transforming into oocysts expressing the CSP protein are substantially reduced. Finally, using the yeast two-hybrid system we also show that Pbs25 has the capacity to homodimerise as well as to form heterodimers with Pbs21.

The glutamate dehydrogenase GENE of Drosophila melanogaster: molecular analysis and expression

Glutamate dehydrogenase is an enzyme that, in addition to its role in the energy metabolism in mitochondria, is involved in neuromuscular transmission. Here we present the structure and sequence of the Gdh gene of Drosophila melanogaster, as well as the analysis of its spatial and temporal pattern of expression. Unlike all other organisms analyzed so far, two forms of the enzyme, differing by the inclusion of 13 extra amino acids, are found in the fruitfly. We show the presence of Gdh mRNA in several tissues of the developing embryo, including the central nervous system, muscles and the alimentary tract. Moreover, we detect the localization of the Gdh protein in specific areas of the muscles, a fact that is consistent both with an involvement in energy metabolism and the role of glutamate as the major neuromuscular transmitter in Drosophila.

Promoter sequences of the putative Anopheles gambiae apyrase confer salivary gland expression in Drosophila melanogaster

The saliva of blood-feeding arthropods contains an apyrase that facilitates hematophagy by inhibiting the ADP-induced aggregation of the host platelets. We report here the isolation of a salivary gland-specific cDNA encoding a secreted protein that likely represents the Anopheles gambiae apyrase. We describe also two additional members of the apyrase/5'-nucleotidase family. The cDNA corresponding to the AgApyL1 gene encodes a secreted protein that is closely related in sequence to the apyrase of the yellow fever mosquito, Aedes aegypti, and whose expression appears enriched in, but not restricted to, female salivary glands. The AgApyL2 gene was found searching an A. gambiae data base, and its expression is restricted to larval stages. We isolated the gene encoding the presumed A. gambiae apyrase (AgApy) and we tested its putative promoter for the tissue-specific expression of the LacZ gene from Escherichia coli in transgenic Drosophila melanogaster. All the transgenic lines analyzed showed a weak but unambiguous staining of the adult glands, indicating that some of the salivary gland-specific transcriptional regulatory elements are conserved between the malaria mosquito and the fruit fly. The availability of salivary gland-specific promoters may be useful both for studies on vector-parasite interactions and, potentially, for the targeted tissue-specific expression of anti-parasite genes in the mosquito.

The mitochondrial genome of the mediterranean fruit fly, Ceratitis capitata

The complete sequence of the mitochondrial genome of Ceratitis capitata has been determined. The circular genome is 15 980 bp long and contains a standard gene complement, i.e. the large and small ribosomal RNA subunits, twenty-two transfer RNA (tRNA) genes and thirteen genes encoding mitochondrial proteins. When comparing the sequence to fragments previously sequenced from other isolates it becomes apparent that interstrain polymorphisms are not rare. These differences are potentially useful for the development of diagnostic tools for population analysis applications, such as determining the source of recent introductions. Moreover, they could help obtain a solution to the long-lasting controversy on the possible eradication of the Medfly from certain locations.

From sequence to chromosome: the tip of the X chromosome of D. melanogaster

One of the rewards of having a Drosophila melanogaster whole-genome sequence will be the potential to understand the molecular bases for structural features of chromosomes that have been a long-standing puzzle. Analysis of 2.6 megabases of sequence from the tip of the X chromosome of Drosophila identifies 273 genes. Cloned DNAs from the characteristic bulbous structure at the tip of the X chromosome in the region of the broad complex display an unusual pattern of in situ hybridization. Sequence analysis revealed that this region comprises 154 kilobases of DNA flanked by 1.2-kilobases of inverted repeats, each composed of a 350-base pair satellite related element. Thus, some aspects of chromosome structure appear to be revealed directly within the DNA sequence itself.