Down syndrome and congenital heart disease: why the regional difference as observed in the Libyan experience?

Background

Children with Down syndrome (DS) have about a 40 to 50% incidence of congenital heart disease (CHD). The objectives of this study were to evaluate the distribution and frequency of CHD patterns in Libyan children with DS.

Methods

All patients with DS who were referred to the cardiology clinic between January 1995 and December 2008 were reviewed.

Results

Of the 1 193 patients reviewed, 537 (45%) had an associated CHD. Overall there were 349 (65%) patients who had a single cardiac lesion, and 188 (35%) had multiple cardiac lesions. The most common isolated cardiac lesion was atrial septal defect (ASD), found in 125 (23%) patients, followed by atrioventricular septal defect (AVSD) in 103 (19%), and ventricular septal defect (VSD) in 76 (14%).

Conclusion

Atrial septal defect was the most common cardiac lesion. The distribution of CHDs in Libyan children with DS was similar to what has been reported internationally, but the frequency was not compared with international rates.     

Selective siRNA-mediated suppression of 5-HT1A autoreceptors evokes strong anti-depressant-like effects

Depression is a major health problem worldwide. Most prescribed anti-depressants, the selective serotonin reuptake inhibitors (SSRI) show limited efficacy and delayed onset of action, partly due to the activation of somatodendritic 5-HT(1A)-autoreceptors by the excess extracellular serotonin (5-HT) produced by SSRI in the raphe nuclei. Likewise, 5-HT(1A) receptor (5-HT(1A)R) gene polymorphisms leading to high 5-HT(1A)-autoreceptor expression increase depression susceptibility and decrease treatment response. In this study, we report on a new treatment strategy based on the administration of small-interfering RNA (siRNA) to acutely suppress 5-HT(1A)-autoreceptor-mediated negative feedback mechanisms. We developed a conjugated siRNA (C-1A-siRNA) by covalently binding siRNA targeting 5-HT(1A) receptor mRNA with the SSRI sertraline in order to concentrate it in serotonin axons, rich in serotonin transporter (SERT) sites. The intracerebroventricular (i.c.v.) infusion of C-1A-siRNA to mice resulted in its selective accumulation in serotonin neurons. This evoked marked anti-depressant-like effects in the forced swim and tail suspension tests, but did not affect anxiety-like behaviors in the elevated plus-maze. In parallel, C-1A-siRNA administration markedly decreased 5-HT(1A)-autoreceptor expression and suppressed 8-OH-DPAT-induced hypothermia (a pre-synaptic 5-HT(1A)R effect in mice) without affecting post-synaptic 5-HT(1A)R expression in hippocampus and prefrontal cortex. Moreover, i.c.v. C-1A-siRNA infusion augmented the increase in extracellular serotonin evoked by fluoxetine in prefrontal cortex to the level seen in 5-HT(1A)R knockout mice. Interestingly, intranasal C-1A-siRNA administration produced the same effects, thus opening the way to the therapeutic use of C-1A-siRNA. Hence, C-1A-siRNA represents a new approach to treat mood disorders as monotherapy or in combination with SSRI.     

Tempo and mode of inhibitor-mutagen antiviral therapies: a multidisciplinary approach

The continuous emergence of drug-resistant viruses is a major obstacle for the successful treatment of viral infections, thus representing a persistent spur to the search for new therapeutic strategies. Among them, multidrug treatments are currently at the forefront of pharmaceutical, clinical, and computational investigation. Still, there are many unknowns in the way that different drugs interact among themselves and with the pathogen that they aim to control. Inspired by experimental studies with picornavirus, here, we discuss the performance of sequential vs. combination therapies involving two dissimilar drugs: the mutagen ribavirin and an inhibitor of viral replication, guanidine. Because a systematic analysis of viral response to drug doses demands a precious amount of time and resources, we present and analyze an in silico model describing the dynamics of the viral population under the action of the two drugs. The model predicts the response of the viral population to any dose combination, the optimal therapy to be used in each case, and the way to minimize the probability of appearance of resistant mutants. In agreement with the theoretical predictions, in vitro experiments with foot-and-mouth disease virus confirm that the suitability of simultaneous or sequential administration depends on the drug doses. In addition, intrinsic replicative characteristics of the virus (e.g., replication through RNA only or a DNA intermediate) play a key role to determine the appropriateness of a sequential or combination therapy. Knowledge of several model parameters can be derived by means of few, simple experiments, such that the model and its predictions can be extended to other viral systems.     

Prenatal study of common submicroscopic “genomic disorders” using MLPA with subtelomeric/microdeletion syndrome probe mixes,among gestations with ultrasound abnormalities in the first trimester

PurposeThe present study aims to investigate the presence of common submicroscopic chromosomal rearrangements in fetuses with ultrasound abnormalities or positive screening in the first trimester and normal karyotype. We used the multiplex ligation-dependent probe amplification (MLPA) technique with subtelomeric (SALSA P036B) and microdeletion syndrome (SALSA P064B/P096) probe mixes as a screening method to measure copy number changes on the tested probes in chorionic villus sampling.MLPA with P036B and P064/P096 probe mixes was performed on 49 chorionic villi DNA samples obtained between the 11th and 13th week of gestation.ResultsThe MLPA analyses did not detect any diminished or increased intensity for all the tested probes in the samples.ConclusionsOur results suggest that the common submicroscopic “genomic disorders” (microdeletion and microduplication syndromes) would not be frequently detected in the first trimester anomalies screening.     

Mode of collection does not influence haematopoietic content of umbilical cord blood units from caesarean deliveries

BACKGROUND: Collection strategy is the first step for collecting good quality cord blood units. There are two main different techniques for collecting cord blood from the umbilical vein: in the delivery room while the placenta is still in the utero by midwifes and obstetricians, or in an adjacent room after placental delivery by cord blood bank trained personal. Our aim was to evaluate the benefits and disadvantages between the two different cord blood collection strategies in caesarean deliveries. METHODS: We retrospectively analysed data of cord blood units collected from caesarean deliveries for a 3-year period. Caesarean section was performed with a low uterine transversal incision in all patients according to common obstetrical practice. Cord blood collection was performed before or after placental delivery. RESULTS: Obstetrical and umbilical cord blood data was obtained from 253 caesarean deliveries. No statistically significant difference was observed for obstetrical variables or cord blood variables except for Hct and platelets. CONCLUSIONS: We conclude both methods produce comparable TNC, CD34 and CFU counts of cord blood units collected from caesarean sections. Before placental delivery collection avoids the financial investment that generates the presence of cord blood banking personal in the maternity ward.     

The Simplified Comorbidity Index predicts non-relapse mortality in reduced-intensity conditioning allogeneic haematopoietic cell transplantation

Comorbidity assessment before allogeneic haematopoietic cell transplantation (allo-HCT) is essential for estimating non-relapse mortality (NRM) risk. We previously developed the Simplified Comorbidity Index (SCI), which captures a small number of ‘high-yield’ comorbidities and older age. The SCI was predictive of NRM in myeloablative CD34-selected allo-HCT. Here, we evaluated the SCI in a single-centre cohort of 327 patients receiving reduced-intensity conditioning followed by unmanipulated allografts from HLA-matched donors. Among the SCI factors, age above 60, mild renal impairment, moderate pulmonary disease and cardiac disease were most frequent. SCI scores ranged from 0 to 8, with 39%, 20%, 20% and 21% having scores of 0–1, 2, 3 and ≥4 respectively. Corresponding cumulative incidences of 3-year NRM were 11%, 16%, 22% and 27%; p = 0.03. In multivariable models, higher SCI scores were associated with incremental risks of all-cause mortality and NRM. The SCI had an area under the receiver operating characteristic curve of 65.9%, 64.1% and 62.9% for predicting 1-, 2- and 3-year NRM versus 58.4%, 60.4% and 59.3% with the haematopoietic cell transplantation comorbidity index. These results demonstrate for the first time that the SCI is predictive of NRM in patients receiving allo-HCT from HLA-matched donors after reduced-intensity conditioning.