Giant Aortic Arch Aneurysm After Interrupted Aortic Arch Repair

An 8-year-old boy developed a large aneurysm of the aortic arch after neonatal complete repair of interrupted aortic arch type B and closure of a perimembranous ventricular septal defect. To our knowledge, this unusual complication has not been previously reported in the English literature.     

Decreased expression of the GABAA receptor in fragile X syndrome

After our initial discovery of under expression of the GABA(A) receptor delta subunit in a genome wide screening for differentially expressed mRNAs in brain of fragile X mice, a validated model for fragile X mental retardation syndrome, we analyzed expression of the 17 remaining subunits of the GABA(A) receptor using real-time PCR. We confirmed nearly 50% under expression of the delta subunit and found a significant 35%-50% reduction in expression of 7 additional subunit mRNAs, namely alpha(1), alpha(3), and alpha(4), beta(1) and beta(2) and gamma(1) and gamma(2), in fragile X mice compared to wild-type littermates. In concordance with previous results, under expression was found in cortex, but not in cerebellum. Moreover, decreased expression of specific GABA(A) receptor subunits in fragile X syndrome seems to be an evolutionary conserved hallmark since in the fragile X fly (Drosophila melanogaster) model we also found almost 50% under expression of all 3 subunits which make up the invertebrate GABA receptor, namely Grd, Rdl and Lcch3. In addition, we demonstrated a direct correlation between the amount of dFmrp and the expression of the GABA receptor subunits Rdl and Grd. Our results add evidence to previous observations of an altered GABAergic system in fragile X syndrome. Because GABA(A) receptors are the major inhibitory receptors in brain, involved in anxiety, depression, insomnia, learning and memory and epilepsy, processes also disturbed in fragile X patients, the well described GABA(A) receptor pharmacology might open new powerful opportunities for treatment of the behavioral and epileptic phenotype associated with fragile X syndrome.     

Revising the Upper Limit of Normal for Levels of Serum Alanine Aminotransferase in a Middle Eastern Population with Normal Liver Histology

Background

Recently, the upper limits of normal (ULN) for alanine-aminotransferase (ALT) has been recommended to be lowered to ≤30 U/l in men and ≤19 U/l in women.

Aim

To evaluate the ALT concentrations in a healthy Middle Eastern population with biopsy-proven normal liver tissue.

Methods

ALT values were calculated from 175 consecutive Saudi potential living liver donors who underwent a liver biopsy as part of a stepwise pretransplant workup.

Results

The mean age of the 110 potential donors with normal liver histology was 27 ± 6.2 years for men and 38.6 ± 7.1 years for women. The mean body mass index (BMI) levels were 23.0 ± 3.5 kg/m² for men and 24.7 ± 3.25 kg/m² for women, and the ALT levels were higher in male patients (22.6 ± 9 vs. 16.4 U/l ± 8, p value = 0.003). Multivariate linear regression showed that BMI and sex were independent variables that were positively associated with the levels of ALT (p < 0.0001). Moreover, when we analyzed donors according to the Prati criteria, 63 (36.0 %) of the individuals were classified into this subgroup. The mean ALT concentration was 12.9 U/l ± 4.5 in women and 19.7 U/l ± 6.9 in men, and these values were significantly lower than those obtained from subjects who did not fit the Prati criteria (19.4 U/l ± 1.8, p = 0.04 for women and 29.0 U/l ± 12.1, p = <0.0001 for men). Thus, we calculated healthy ALT values of 33 IU/l for men and 22 IU/l for women.

Conclusions

The ULN for ALT levels in Middle Eastern populations should be lowered, including separate values for males and females. Furthermore, metabolic parameters were shown to have a significant effect on ALT levels.     

Microvesicles from patients with acute coronary syndrome enhance platelet aggregation

Abstract

Microvesicles (MVs) released from leukocytes, platelets and endothelial cells are elevated in patients with acute coronary syndrome (ACS). In the present study, we assessed the potential pro-aggregatory properties of MVs obtained from ACS patients. Thus, we divided the patients into two groups based on clopidogrel-responsiveness, i.e. high on-treatment platelet reactivity (HPR; n?=?16), and low or normal on-treatment platelet reactivity (non-HPR; n?=?14), respectively. MVs from patients were obtained by high-speed centrifugation, and the pro-aggregatory effect of MVs added to fresh isolated platelets from healthy subjects were analyzed by 96-well microplate aggregometry. MVs from HPR patients significantly enhanced spontaneous platelet aggregation around two times more than MVs from non-HPR patients. The pro-aggregatory effect of three out of four MV phenotypes correlated to MV-concentrations as determined by flow cytometry. Furthermore, MVs from patients with diabetes mellitus (n?=?9) had a stronger pro-aggregatory effect compared to MVs from those without diabetes (n?=?21; p?=?.025 between groups). In conclusion, MVs from ACS patients with clopidogrel non-responsiveness enhance platelet aggregation, as do MVs from ACS patients with diabetes. Thus, MVs from patients with hyperreactive platelets boost platelet aggregation. Blocking MV-formation may reduce platelet hyperreactivity.     

Prediction of death in the SMNΔ7 mouse model of spinal muscular atrophy: Insight into disease stage and progression

Proximal Spinal Muscular Atrophy (SMA) is a debilitating neuromuscular disease and a leading inherited genetic cause of infant death. To date, there is no effective treatment for SMA. The SMNΔ7 neonatal mouse model of SMA recapitulates key features of the severe form of SMA and remains a valuable tool in preclinical drug discovery. At any particular postnatal age (P), the disease progression in the SMNΔ7 mouse model is not universal, as some animals die as early as the day of birth and others live for up to three weeks. Identification of the disease stage in SMNΔ7 mice, independent of age, would aid in the design and interpretation of preclinical studies. We developed a score (CD score), derived from body weight analysis, that allowed us to gain insight into the disease progression and predict death. Respiratory complication is a leading cause of mortality in the SMA patient and this phenotype has been reported in severe mouse models of SMA. We subsequently measured muscle and brain tissue lactate levels, an indirect measure of hypoxia, in SMNΔ7 mice at P10 and correlated these measures to respiratory rate. SMNΔ7 mice showed a significant increase in tissue lactate and a decrease in respiratory rate in comparison to control. The CD score correlates linearly with tissue lactate level and respiratory rate. The finding of lactate buildup in the SMNΔ7 mouse and the correlation with a score that is predictive of disease stage provide an interesting insight into the disease pathophysiology and a possible biomarker for SMA.     

Use of peripheral blood instead of bone marrow to monitor residual disease in children with acute lymphoblastic leukemia

In children with acute lymphoblastic leukemia (ALL), response to treatment is assessed by bone marrow aspiration. We investigated whether minimal residual disease (MRD) can be effectively monitored in peripheral blood. We used flow cytometric techniques capable of detecting 1 leukemic cell among 10 000 or more normal cells to compare MRD measurements in 718 pairs of bone marrow and peripheral blood samples collected from 226 children during treatment for newly diagnosed ALL. MRD was detected in marrow and blood in 72 pairs and in marrow but not in blood in 67 pairs; it was undetectable in the remaining 579 pairs. Remarkably, findings in marrow and blood were completely concordant in the 150 paired samples from patients with T-lineage ALL: for each of the 35 positive marrow samples, the corresponding blood sample was positive. In B-lineage ALL, however, only 37 of 104 positive marrow samples had a corresponding positive blood sample. Notably, peripheral blood MRD in these patients was associated with a very high risk for disease recurrence. The 4-year cumulative incidence of relapse in patients with B-lineage ALL was 80.0% +/- 24.9% for those who had peripheral blood MRD at the end of remission induction therapy but only 13.3% +/- 9.1% for those with MRD confined to the marrow (P =.007). These results indicate that peripheral blood may be used to monitor MRD in patients with T-lineage ALL and that peripheral blood MRD may provide strong prognostic information in patients with B-lineage ALL.     

Gadolinium effect on thalamus and whole brain tissue segmentation

Purpose

Gadolinium-based contrast agent (GBCA) effect on automated segmentation algorithms of subcortical gray matter (GM) is not fully known. The aim of this study is to determine gadolinium effect on the segmentation of the thalamus and whole brain tissue using different automated segmentation techniques.

Methods

Eighty-four multiple sclerosis (MS) patients underwent an MRI acquisition of two 3DT1-weighted sequences with and without gadolinium injection among which 10 were excluded after image quality check. Manual thalamic segmentation considered as gold standard was performed on unenhanced T1 images. volBrain and FSL-Anat were used to automatically segment the thalamus on both enhanced and unenhanced T1 and the degree of similitude (DICE) values were compared between manual and automatic segmentations. Whole brain tissue segmentation (GM, white matter (WM), and lateral ventricles (LV)) was also performed using SIENAX. A paired samples t test was applied to test the significance of DICE value differences between the thalamic manual and automatic segmentations of both enhanced and unenhanced T1 images.

Results

Significant differences (FSL-Anat 1.474% p?<?0.001 and volBrain 1.990% p?<?0.001) in DICE between thalamic manual and automatic segmentations on both enhanced and unenhanced images were observed. Automatic tissue segmentation showed a mean DICE of 81.5%, with LV having the lowest DICE value (74.2%). When compared to tissue segmentations, automatic thalamic segmentations by FSL-Anat or volBrain demonstrated a higher degree of similitude (FSL-Anat?=?91.7% and volBrain?=?90.7%).

Conclusion

Gadolinium has a significant effect on subcortical GM segmentation. Although significant, the observed subtle changes could be considered acceptable when used for region-based analysis in perfusion or diffusion imaging.