Stripe and Short Range Order in the Charge Density Wave of 1T-Cu_{x}TiSe_{2}.

We study the impact of Cu intercalation on the charge density wave (CDW) in 1T-Cu_{x}TiSe_{2} by scanning tunneling microscopy and spectroscopy. Cu atoms, identified through density functional theory modeling, are found to intercalate randomly on the octahedral site in the van der Waals gap and to dope delocalized electrons near the Fermi level. While the CDW modulation period does not depend on Cu content, we observe the formation of charge stripe domains at low Cu content (x<0.02) and a breaking up of the commensurate order into 2×2 domains at higher Cu content. The latter shrink with increasing Cu concentration and tend to be phase shifted. These findings invalidate a proposed excitonic pairing as the primary CDW formation mechanism in this material.

Doping nature of native defects in 1T-TiSe2.

The transition-metal dichalcogenide 1T-TiSe2 is a quasi-two-dimensional layered material with a charge density wave (CDW) transition temperature of T(CDW) ≈ 200 K. Self-doping effects for crystals grown at different temperatures introduce structural defects, modify the temperature-dependent resistivity, and strongly perturbate the CDW phase. Here, we study the structural and doping nature of such native defects combining scanning tunneling microscopy or spectroscopy and ab initio calculations. The dominant native single atom dopants we identify in our single crystals are intercalated Ti atoms, Se vacancies, and Se substitutions by residual iodine and oxygen.

Possible heterochromatin horizontal spread through non-homologous chromosome associations in pachytene chromocenters of Ctenomys Rodents.

Heterochromatin patterns were analyzed in the genus Ctenomys from Uruguay which exhibits high karyotype variability. Different amounts and localizations of heterochromatin were observed in species and populations analyzed. While species as C. rionegrensis presented heterochromatic arms in all the chromosomes of the karyotype, other species like C. torquatus showed only few chromosomes with pericentric heterochromatin. At the pachytene stage, bivalents merge in densely stained chromocenters. We detected in these chromocenters the typical highly repeated DNA of this genus after in situ hybridization, the M31 chromodomain through immunofluorescence as well as dense Giemsa staining after C-banding. In species that present low amounts of heterochromatin, only 1 or 2 chromocenters were observed in which bivalents merge as observed in C. rionegrensis. After BRCA1 immunodetection we observed in early pachytene cells positive spots located over heterochromatic chromocenters that strongly suggest heterochromatic DNA repair. Mechanical stress mainly due to increasing chromatin compactness before metaphase I might be a mechanism to spread heterochromatin between different chromosomes within a karyotype.

Asymmetric staining of Ctenomys chromosomes after treatment with AluI restriction nuclease.

After treatment with the endonuclease AluI for 6 or 24 h, chromosomes of two populations of the South American rodent Ctenomys presented an asymmetric banding pattern after Giemsa staining. These asymmetric patterns were chromosome specific (each chromosome of a pair showed different banding pattern) but constant from cell to cell and between homologous chromosomes of the populations analysed. The nature of this peculiar staining is discussed in the light of the interaction between endonucleases and DNA in chromatin of fixed chromosomes.

A novel Mr 77,000 protein of the XY body of mammalian spermatocytes: its localization in normal animals and in Searle's translocation carriers.

We describe a novel XY body protein of rat and mice pachytene spermatocytes called XY77. Biochemical characterization showed that protein XY77 (Mr 77,000; pH value 8.3) is present in meiotic but absent in postmeiotic stages of spermatogenesis. With the aid of an antibody against protein XY77 together with another specific for XY body-associated protein XY40 we also investigated the localization of these proteins in mice carrying Searle's translocation, a reciprocal X-autosomal translocation. We show here that in these mice the distribution of both XY77 and XY40 is abnormal. Our results indicate that in Searle's translocation alterations are not restricted to the translocated autosome, but also involve chromatin segments corresponding originally to the sex chromosomes X and Y.

Use of the paediatric bronchoscope, flexible and rigid, in 51 European centres.

We have undertaken a survey to establish current practices and differences in the use of bronchoscopes in children in European centres. A questionnaire was sent to all 220 members of the Paediatric Assembly of the European Respiratory Society (ERS). The questions concerned the following points: indications for bronchoscopy; site of bronchoscopy; type of sedation; any oxygen supplementation during the procedure; number of procedures performed in the previous 12 months; number of procedures performed in the neonatal intensive care unit; number of bronchoalveolar lavages (BALs); side-effects during and after the procedures; and diagnostic yield. Fifty one European centres (40.8% of the European centres contacted) took part in the study. A total of 7,446 bronchoscopies had been performed in the last 12 months: 4,587 using the flexible bronchoscope and 2,859 using the rigid bronchoscope. At centres using only the fibreoptic bronchoscope, the most frequent indication was "recurrent/persistent pneumonia" (17%); at centres using only the rigid bronchoscope, it was "foreign body inhalation" (36.7%); at centres using both methods, the most frequent indication was "other indications" (23.9%). In 12 months, 2,231 BALs were performed: 1,419 in immunocompetent children and 812 in immunocompromised patients. In centres using only the fibreoptic bronchoscope, the highest yield was for "stridor" (81%); in centres using only the rigid bronchoscope, the highest yield was for "persistent atelectasis" (68%); and in centres using both instruments, it was for "foreign body inhalation" (93%). The results of the study suggest that bronchoscopy in children is now a well-established procedure at several European centres, while others are just beginning to use this technique.

Problems with the retrieval of long-standing inhaled foreign bodies in children.

In the last 7 yrs, we have removed 51 foreign bodies inhaled by children. In five cases involving long-standing foreign bodies, retrieval of the inhaled objects was complicated by their peripheral location in the bronchial tree and by the presence of abundant granulation tissue. In two of these children, the inhaled foreign bodies had been pushed further down the bronchial tree during a previous unsuccessful bronchoscopy. The use of a rigid bronchoscope with optical peanut forceps and 2-4 doses of an aqueous solution of epinephrine 1:100,000, at the dosage of 0.1 mL.kg-1.body weight (during removal of granulation tissue and after removal of the foreign bodies) permitted the complete removal of the foreign bodies in one session and a good control of bleeding.

Cytogenetic and molecular analysis of the satellite DNA of the genus Ctenomys (Rodentia Octodontidae) from Uruguay.

The genus of subterranean rodents Ctenomys presents the widest range of variability in diploid number among mammals (from 2n = 10 to 2n = 70). In Uruguay, this variability is observed in karyotypes with 2n = 44, 50 or 58 and two geographically isolated populations with 70 chromosomes but different karyotypic structure. The last three populations were analyzed in the present study. They present a satellite DNA, which was isolated from genomic DNA after AluI digestion. In situ hybridization showed that this satellite DNA is located in the centromeric region of a few chromosomes, coincident with Hoechst 33258 staining and C-banding patterns. A similar satellite DNA was detected in Argentinian species of this genus. We established that, in spite of differences in number of positive heterochromatic blocks per karyotype, the C value is the same in the three populations studied. The nature and possible evolutionary path of this repeated DNA is discussed.

The first 20 minutes after a single dose of inhaled salmeterol in asthmatic children.

Very little is known as yet about the effect of salmeterol in pediatric asthma, so a trial was performed on children with mild asthma to compare salmeterol with salbutamol in terms of how quickly they took effect. The double-blind study involved 11 children (mean age 13.4 years) randomly assigned to inhale salmeterol 50 micrograms, salbutamol 200 micrograms, or a placebo three times on alternate days. Peak expiratory flow (PEF), heart rate, and blood pressure were measured before and 5, 10, 15, and 20 min after administering the medication. With salbutamol, PEF was higher at 5 and 10 min, subsequently dropping off at 15 and 20 min; with salmeterol, PEF was better at 10 and 20 min. Forced expiratory volume at 1 s (FEV1) measurements taken at the baseline and after 10 and 20 min revealed an important and consistent rise in values after salmeterol, whereas salbutamol was more effective after 10 min than after 20 min. No significant changes were recorded in heart rate or blood pressure after salbutamol; after salmeterol, there was a significant increase in heart rate after 5 min, but not at subsequent measurements. In conclusion, salmeterol begins to take effect already within 10 min of a single administration in asthmatic children, although the onset of its effect is slower than with salbutamol.

Use of fiberoptic bronchoscopy in asthmatic children with lung collapse.

Segmental atelectasis during asthmatic attacks as a consequence of bronchospasm and hypersecretion are very frequent in children. The collapse of a lung instead is a very rare occurrence. We report two patients with acute exacerbation of asthma, showing an in complete response to bronchodilatory therapy. The clinical findings and chest X-ray were suggestive for collapse of a lung. An urgent fiberoptic bronchoscopy revealed obstruction of a stem main bronchus caused by sticky mucopurulent secretions. The aspiration improved dramatically the respiratory distress and the radiological picture. In these cases we recommended to perform an immediate bronchial aspiration by means of a flexible instrument without waiting a further deterioration of respiratory function before taking this decision.

Serum and bile bilirubin pigments in the differential diagnosis of Crigler-Najjar disease.

OBJECTIVE: To differentiate between Crigler-Najjar (CN) disease types 1 and 2. DESIGN: The patterns of serum bilirubins, bile pigment composition, and phenobarbital response were studied. PATIENTS: Three infants, affected by high serum unconjugated bilirubin concentrations, previously classified as type 1 CN. METHODS: Serum and bile bilirubin pigment composition, both before and after phenobarbital (PB) treatment, were determined by alkaline methanolysis and high-pressure liquid chromatography. PB was given for at least 3 weeks by oral administration (5 mg/kg bw per day). RESULTS: No diconjugated bilirubin was found either before or after PB treatment in the serum of the three studied infants. In two patients traces of monoconjugated bilirubin were detected before PB therapy, and the ratio of conjugated/total bilirubin (percent) was increased by the PB response. In the third patient, traces of monoconjugated bilirubin appeared only after PB administration. However, the serum unconjugated bilirubin concentration decreased significantly only in the second patient, following the second cycle of PB treatment, leading to the diagnosis of type 2 CN. The analysis of the methyl ester derivatives of bile pigments was also performed on bile samples obtained in two patients by Entero-Test (R) both before and after PB treatment. An absolute increment in monoesterified bilirubin concentration was found after PB administration, although the percent concentration increased in one case and decreased in the other. No diesterified bilirubin was detected in the bile samples. CONCLUSIONS: The present results show that in types 1 and 2 CN disease it is possible to detect traces of monoconjugated but not diconjugated bilirubin both in serum and in bile. Whereas PB treatment is effective in slightly increasing the serum monoconjugated bilirubin concentration even in type 1 CN disease, the diagnosis of type 1 or 2 is based on finding a substantial decrease of serum unconjugated bilirubin following PB administration.

[Misdiagnosis of asthma. Two paradigmatic case reports]. / Diagnosi errata di asma bronchiale. Due casi paradigmatici.

We present two children, respectively five and six years old, misdiagnosed and treated as asthmatics in allergological centers. After admission to our department, endobronchial inflammatory pseudotumor and lung tuberculosis were diagnosed respectively. While endobronchial pseudotumor is rather rare, lung tuberculosis is a less rare diagnosis that must be considered in patients with a history of persistent and recurrent coughing with or without wheezing, especially when there is no family history of atopical diseases and skin allergic tests are negative, and the social and economic conditions at risk.

Predeposit hemodilution and intra- and post-operative blood salvage in the orthopaedic surgery of brain damaged children.

The advantages of autologous transfusion are nowadays well known. It appears so very important to enlarge to the greatest number of kinds of pathologies, trying to overcome all possible problems and studying every counterindication. In this study, through a strict collaboration among orthopaedics, anaesthesia, transfusion medicine, neurological and pediatric specialists, we studied a peculiar protocol, suitable for enlarging the autologous techniques to brain damaged children and, after a regular application lasted globally for about two years, we did an evaluation of the results.