A radio ridge connecting two galaxy clusters in a filament of the cosmic web.

Galaxy clusters are the most massive gravitationally bound structures in the Universe. They grow by accreting smaller structures in a merging process that produces shocks and turbulence in the intracluster gas. We observed a ridge of radio emission connecting the merging galaxy clusters Abell 0399 and Abell 0401 with the Low-Frequency Array (LOFAR) telescope network at 140 megahertz. This emission requires a population of relativistic electrons and a magnetic field located in a filament between the two galaxy clusters. We performed simulations to show that a volume-filling distribution of weak shocks may reaccelerate a preexisting population of relativistic particles, producing emission at radio wavelengths that illuminates the magnetic ridge.

[Carcinoid of Vater's papilla. The authors' own experience]. / Il carcinoide della papilla di Vater. Esperienza personale.

Carcinoid tumours of the papilla of Vater, like all those of the gastroenteric tract, belong to the PUD system: in fact they excrete different amines and polypeptidic hormones that cause articulated and complex clinical features. We describe the clinical picture of a non secreting carcinoid tumour in a patient suffering from cholelithiasis in who jaundice has appeared after video-laparocholecystectomy; ERCP detected a papillary neoplasia which proved to be a carcinoid tumour at immunohistochemical investigation. The patient was submitted to surgical removal of the neoplasia by the trans-duodenal way. This kind of operation was chosen considering the small dimension of the tumour, the absence of lymph nodal and hepatic involvement and the elevated risk of pancreaticoduodenectomy. Eight months later hematic gastrine, NSE and total body scintigraphy with octreotide have shown normal values and the patients is in good clinical condition. The diagnosis of these tumours is always difficult when the typical hormonal syndrome is not present. The prognosis of this kind of tumours is better than others of the gastrointestinal tract due to the early symptoms (jaundice), and, consequently, of the treatment. A strict follow-up is recommended in these patients because a resumption of the tumour could also appear many years after the surgical intervention.

The care of the limb deficient child in Venezuela.

An overview of the situation in Venezuela is made by sampling the cases of congenital limb deficiency treated at the Hospital San Juan de Dios in Caracas from 1961-1989. The major longitudinal deficiencies are analysed. The socioeconomic situation of the patients is of most importance being the cause of final decisions in relation to surgery, the ordering of prosthesis and orthosis, supplied mainly by the Venezuelan Institute of Social Security (IVSS), the maintenance of these items and the possibility of travelling to the hospital for diagnosis, treatment and follow-up. All these transform the situation from a medical problem into a socio-economic problem typical of a third world country.

Characterization of bacteriophages infecting Streptomyces erythreus and properties of phage-resistant mutants.

Three bacteriophages infecting Streptomyces erythreus, called G3, G4 and G5, were isolated and characterized. They contain double-stranded linear DNA molecules with cohesive ends. The restriction map of G3 DNA (48 kilobases long) for four restriction endonucleases and that of G4 DNA (43 kilobases long) for seven restriction endonucleases are reported. Restriction analysis and hybridization experiments showed that G3 and G4 share little DNA homology, while G4 and G5 are apparently identical except for an additional EcoRI site present in G5. The region containing this EcoRI site has been mapped on G4 DNA. Microbiological and serological data showed that G5 is very similar to G4. G3- and G4-resistant mutants of S. erythreus PS1 were isolated. The screening of phage-resistant mutants showed a high frequency of strains with increased erythromycin production. The mechanism of phage resistance of strain PS3 (G3 resistant) and of strain PS16 (G4 resistant) was examined. The DNA of the resistant strains contains no phage DNA, ruling out lysogeny as a cause of phage resistance. Transfection of strains PS1, PS3, and PS16 with DNA of the three phages showed the same efficiency, indicating that resistance is at the level of the bacterial wall.