Phase Transition, Dielectric Properties, and Ionic Transport in the [(CH3)2NH2]PbI3 Organic-Inorganic Hybrid with 2H-Hexagonal Perovskite Structure.

In this work, we focus on [(CH3)2NH2]PbI3, a member of the [AmineH]PbI3 series of hybrid organic-inorganic compounds, reporting a very easy mechanosynthesis route for its preparation at room temperature. We report that this [(CH3)2NH2]PbI3 compound with 2H-perovskite structure experiences a first-order transition at ≈250 K from hexagonal symmetry P63/mmc (HT phase) to monoclinic symmetry P21/c (LT phase), which involves two cooperative processes: an off-center shift of the Pb2+ cations and an order-disorder process of the N atoms of the DMA cations. Very interestingly, this compound shows a dielectric anomaly associated with the structural phase transition. Additionally, this compound displays very large values of the dielectric constant at room temperature because of the appearance of a certain conductivity and the activation of extrinsic contributions, as demonstrated by impedance spectroscopy. The large optical band gap displayed by this material (Eg = 2.59 eV) rules out the possibility that the observed conductivity can be electronic and points to ionic conductivity, as confirmed by density functional theory calculations that indicate that the lowest activation energy of 0.68 eV corresponds to the iodine anions, and suggests the most favorable diffusion paths for these anions. The obtained results thus indicate that [(CH3)2NH2]PbI3 is an electronic insulator and an ionic conductor, where the electronic conductivity is disfavored because of the low dimensionality of the [(CH3)2NH2]PbI3 structure.

Near room temperature dielectric transition in the perovskite formate framework [(CH3)2NH2][Mg(HCOO)3].

We report that the hybrid organic-inorganic compound [(CH3)2NH2][Mg(HCOO)3] shows a marked dielectric transition around Tt∼ 270 K, associated to a structural phase transition from SG R3[combining macron]c (centrosymmetric) to Cc (non-centrosymmetric). This is the highest Tt reported so far for a perovskite-like formate that is thus a promising candidate to display electric order very close to room temperature.

[In-utero antiretroviral exposure and mitochondrial toxicity in a cohort of uninfected infants born to HIV-1-infected women]. / Exposición a antirretrovirales y toxicidad mitocondrial en una cohorte de niños no infectados hijos de madres VIH positivas.

INTRODUCTION: In this study, we attempt to find out the percentage of uninfected infants born to HIV-infected women and exposed in-utero and perinatally to Antiretroviral Treatment (ART) that show high lactate levels, or any other mitochondrial damage markers (such as hypertransaminasaemia or hyperamylasaemia), during the first three months of age. We shall also establish whether certain drugs used in-utero are associated with higher lactate, transaminase or amylase levels. METHODS: We analysed the available data from 623 uninfected infants born in the Spanish FIPSE cohort that were born in the period 2000-2005. The normal values for lactate, transaminases and amylase were set according to AIDS Clinical Groups Trials toxicity tables for infants. RESULTS: The percentages of children with high lactate levels at 0.5; 1.5 and 3 months of age were 48%, 51.4% and 43% among those infants with available data. Respectively, the percentages of children with high AST values were 13.2; 10.4 and 17.2%. The values for high ALT were 3.3%; 3.4% and 5%. The percentages for hyperamylasaemia were 0%; 0.6% and 2.6%. We found no significant difference among the drugs used in utero for the four analysed biochemical markers along the first three months of age. CONCLUSIONS: We have found a high proportion of hyperlactataemia among infants exposed in-utero to ART, as shown in other cohorts of similar characteristics. No morbidity or mortality was communicated to the cohort analysis group. No ART drug among those used in-utero was statistically associated with a higher proportion of high lactate levels in these infants.

Opportunistic infections and organ-specific diseases in HIV-1-infected children: a cohort study (1990-2006).

OBJECTIVES: Highly active antiretroviral therapy (HAART) has dramatically changed the natural history of HIV infection in children, but there are few studies in the literature about the incidence of clinical manifestations after HAART in this population, compared with adults. The aim of this study was to describe the influence of the widespread use of HAART on the development of opportunistic infections and organ-specific diseases in HIV-infected children. METHODS: An observational study of a cohort of 366 vertically HIV-infected children followed from 1990 to 2006 was carried out. According to the main antiretroviral protocol used, three calendar periods (CPs) were defined and compared: CP1 (1990-1996: no patients on HAART), CP2 (1997-1999: <60% on HAART) and CP3 (2000-2006: >60% on HAART). RESULTS: Children experienced a progressive increase in CD4 T cell count (P<0.05) and a decrease in HIV viral load from 1996 onwards (P<0.05). Similarly, rates of death, AIDS, opportunistic infections (bacteraemia, candidosis, cryptosporidiosis and bacterial pneumonia) and organ-specific diseases (wasting syndrome, thrombocytopenia, cardiomyopathy, lymphoid interstitial pneumonia and HIV-associated encephalopathy) were lower in CP2 and CP3 than in CP1. CONCLUSIONS: This study provides evidence of improved clinical outcomes in HIV-infected children over time and shows that mortality, AIDS, opportunistic infections and organ-specific diseases declined as HAART was progressively instituted in this population.

[Growth of uninfected infants exposed to antiretrovirals born to HIV-infected woman]. / Exposición a antirretrovirales y crecimiento en una cohorte de niños no infectados, hijos de madre con VIH positivo.

INTRODUCTION: Recent reports show that Antiretroviral Treatment (ART) during pregnancy does not affect somatic growth of children born to HIV-infected mothers, are reassuring. The aim of this study is to perform an anthropometric analysis of the uninfected children followed in the Spanish FIPSE cohort during their first 18 months of life, and to describe the possible risk factors during pregnancy that may influence low birth weight. METHODS: The FIPSE cohort includes 8 public hospitals in Madrid, and prospectively follows children born to HIV-infected women at these hospitals. We collected data on 601 uninfected children, following standardised protocols, during their first 2 years of life. A P value<0.05 was considered statistically significant. Data from the Pablo Orbegozo Foundation were used to compare the means of our population with the standard weight, longitude an occipitofrontal circumference (OFC) of the Spanish population during the first 18 months of life. RESULTS: The mean weight was 2766g (+/-590), and 2967g (+/-427) when premature neonates were excluded. The proportion of Intrauterine Growth Restriction among non- premature neonates was 19.8% (95% CI: 16.3-23.8). Children born to mothers that used illicit drugs weighed less: 2752g (+/-325) vs. 3002g (+/ 435), P<0.001, as did children born to mothers who smoked during pregnancy: 2842g (+/-363) vs. 3018g (+/-444), P>0.001. Maternal anaemia did not influence the low birth weight of the children when premature neonates were excluded. We found no statistically significant differences depending on the ART received during pregnancy. Children born to mothers who had CD4 > 500 cell /mm were heavier (2834g +/-503) than those whose mothers had CD4 of less than 200 cell/mm (2565g +/-702), P=0.008. These differences disappeared when premature neonates were excluded. Children born to mothers with undetectable viral load were heavier (2866g +/-532 vs. 2704g +/-588, P=0.005), but these differences also disappeared when the prematures were excluded from the analysis. Mean weight, length, and OFC of our population at birth (excluding premature neonates) were lower than the Spanish standards. (z for weight=-0.83; z for length =-1.02; z for OFC=-1.00), but these differences are not statistically significant and disappear at 18 months of age (z for weight=-0.08; z for height=-0.32; z for OFC=-0.31). The type of ART did not have any significant influence. DISCUSSION: There is a very significant difference between the weight of the children born to mothers addicted to illicit drugs and the rest of the children. Similarly, the weight of the children born to smoking mothers is significantly lower. There was no association between maternal anaemia and the type of ART. The children of our population have lower weights, length and OFC at birth, but this may due to the high number of scheduled caesarean births, practised at 38 weeks of pregnancy (54.5%). Our children catch-up with anthropometric measurements during the first and second year of life, and these are similar to Spanish standards at 18 months old.

[Birth defects in a cohort of uninfected children born to HIV-infected women]. / Malformaciones congénitas en una cohorte de niños no infectados, hijos de madres infectadas por el virus de la inmunodeficiencia humana.

INTRODUCTION: Mother-to-Child HIV transmission is now just 1% in western countries, due to prevention measures. Antiretroviral Treatment (ART) drugs do have adverse effects, anaemia and myelosupression caused by cidovudina being the most commonly observed effects. In the present study, we have analysed the proportion and characteristics of congenital malformations (CM) or birth defects (BD) in a cohort of uninfected children born to HIV-infected women. METHODS: A total of 623 uninfected children belonging to the FIPSE cohort were followed up according to standardised protocols. This cohort includes 8 public hospitals from Madrid and follows up HIV-infected pregnant women and their children. Children were classified according to prematurity, ethnic origin, birth weight, withdrawal syndrome, in-utero treatment. Birth defects were described and defined according to the EUROCAT, the European registry for BD. Mild errors of morphogenesis were excluded from the analysis. Categorical variables were compared with the X(2) or the Fisher test. RESULTS: A total of 78% (486) of the mothers were of Caucasian origin; 18.8% (117) used some illicit drug (heroine, cocaine or methadone) during gestation; 51 mothers (8.1%) received no ART, 10 (1.6%) received monotherapy and 469 (75.3%) received HAART. BD were seen in 52 children, with the most frequent being genitourinary and cardiological. Anaemia in the first trimester was an associated risk for BD (17.9% vs. 8.1%, P = 0,04). Similarly, mothers who used any illicit drug (plus methadone), had a slightly higher risk for BD in their offspring (13.8% vs. 7.6%, P = 0,04) There was no increased risk for BD significantly associated with any of the in-utero used antiretrovirals, although Nevirapine use in-utero showed a protective effect. Children born to mothers who received ART in the first trimester had the same rate of BD (7.4%) as those whose mothers started ART in the second trimester (8.8%), P = 0,67. CONCLUSIONS: The proportion of BD that we have observed seems higher than those shown in other European teratogenicity studies and also higher than those shown in cohorts with HIV and antiretroviral exposed infants. This may be due to the fact that our series show the results of an active surveillance system (that includes ultrasound), where BD classically appear in a higher proportion. Immunovirological characteristics of the mother did not influence the proportion of BD, but anaemia in the fist trimester and the use of illicit drugs (or methadone) did. No specific antiretroviral drug was associated with an increase in BD, although Nevirapine showed a possible protective effect in the statistical analysis. Mothers who started antiretrovirals in the first trimester do not have more BD in their offspring than mothers who started on antiretrovirals later on.

[Anaemia and neutropenia in a cohort of non-infected children of HIV-positive mothers]. / Anemia y neutropenia en una cohorte de niños no infectados hijos de madres positivas para el virus de la inmunodeficiencia humana.

INTRODUCTION: Mother-to-child HIV transmission is currently around 1% in western countries, due to prevention measures. Antiretroviral drugs do have adverse effects, anaemia and myelosupression caused by AZT being the most observed effects. In the present study, we analyse the prevalence of anaemia and neutropenia in an uninfected children cohort born to HIV-infected women. MATERIAL AND METHODS: We followed up 623 uninfected children belonging to the FIPSE cohort according to standardised protocols. This cohort groups 8 hospitals from Madrid and follows up HIV infected pregnant women and their children. Anaemia and neutropenia were defined according to the ACTG (AIDS Clinical Trails Group) toxicity tables. Children were classified according to prematurity, ethnic origin, birth weight, withdrawal syndrome, in-utero treatment and neonatal prophylaxis. Categorical variables were compared with the chi2 or the Fisher tests. RESULTS: Anaemia was observed in 188 (30.1%) children during follow-up and 161 (25.8%) had anaemia grade 2 or higher. Prematurity (p < 0.001), low birth weight (p = 0.005) and Highly Active Antiretroviral Treatment (HAART) with Protease Inhibitors (p = 0.016) were associated with higher percentages of anaemia in children. Nadir haemoglobin values were reached by 6 weeks of life and anaemia was transient and disappeared by six months of age. Neutropenia was present in 41.9% (261 children) and 22.7% of the children had moderate-severe neutropenia. Prematurity was again associated with neutropenia (p = 0.01) and low birth weigh was associated only with moderate-severe neutropenia (p = 0.023). African infants had a higher percentage of neutropenia than the rest of the children (50% vs. 44%), although the differences were not significant. The type of in-utero treatment did not appear to influence the neutropenia. Neutropenia was still present in 12.5% of infants at 18 months of age. The type of neonatal prophylaxis to prevent mother-to-child transmission (monotherapy, dual therapy or triple therapy) did not influence either cytopenia. CONCLUSION: In our series, the proportion of children with anaemia is high: 30.1% Prematurity, low birth weight and HAART with IP were associated with a higher proportion of anaemia, which was transient and had little clinical relevance. The proportion of children with neutropenia was higher (41.9%) and was associated with prematurity, low birth weight and African origin. The type of neonatal prophylaxis does not seem to influence the development of cytopenias. Persistence of neutropenia (without clinical significance) was observed in a small percentage of the children 12.5%, at 18 months of age.

Fetal brain disruption sequence in a newborn infant with a history of cordocentesis at 21 weeks gestation.

The case is reported of a full term infant with severe microcephaly, overlapping sutures, prominence of the occipital bone, and scalp rugae. No other associated malformations were observed. The only obstetric history of interest was the performance of cordocentesis at 21 weeks gestational age because of low maternal alpha fetoprotein levels. Ultrasound scans performed until then were normal. Cranial growth retardation was detected on ultrasound scanning at 25 weeks and intrauterine growth retardation as well as severe microcephaly at 34 weeks. Neuroimaging studies performed on the newborn infant showed intense cerebral atrophy in both hemispheres. Other complementary investigations gave negative results. A relation is proposed between the cordocentesis and the development of vascular disruption, which could have caused the fetal brain disruption sequence in this case.

Congenital cutaneous candidiasis: report of four cases and review of the literature.

Congenital cutaneous candidiasis (CCC) is a rare disease acquired by an ascending route, liable to affect the offspring of pregnant women suffering from vulvovaginitis. The cutaneous lesions are present at birth or within the first hours of life. Some infants may present with respiratory distress or clinical signs of sepsis during the first 2 days of life. We report four new cases of CCC, three of which presented transient respiratory distress and clinical signs of sepsis with hepatosplenomegaly. The evolution was favourable in all three cases with topical and oral therapy. We emphasize the self-limited character of this disease, although preterm infants may be at risk of systemic spread. Only one infant presented paronychia as a late complication.