Chromosome 11p15.5 regional imprinting: comparative analysis of KIP2 and H19 in human tissues and Wilms' tumors

The imprinted H19 gene is frequently inactivated in Wilms' tumors (WTs) either by chromosome 11p15.5 loss of heterozygosity (LOH) or by hypermethylation of the maternal allele and it is possible that there might be coordinate disruption of imprinting of multiple 11p15.5 genes in these tumors. To test this we have characterized total and allele- specific mRNA expression levels and DNA methylation of the 11p15.5 KIP2 gene in normal human tissues, WTs and embryonal rhabdomyosarcoma (RMS). Both KIP2 alleles are expressed but there is a bias with the maternal allele contributing 70-90% of mRNA. Tumors with LOH show moderate to marked reductions in KIP2 mRNA relative to control tissues and residual mRNA expression is from the imprinted paternal allele. Among WTs without LOH most cases with H19 inactivation also have reduced KIP2 expression and most cases with persistent H19 expression have high levels of KIP2 mRNA. In contrast to the extensive hypermethylation of the imprinted H19 allele, both KIP2 alleles are hypomethylated and WTs with biallelic H19 hypermethylation lack comparable hypermethylation of KIP2 DNA. 5-aza-2'-deoxycytidine (aza-C) increases H19 expression in RD RMS cells but does not activate KIP2 expression. These data indicate coordinately reduced expression of two linked paternally imprinted genes in most WTs and also suggest mechanistic differences in the maintenance of imprinting at these two loci.      

A founder mutation in the PEX6 gene is responsible for increased incidence of Zellweger syndrome in a French Canadian population

ABSTRACT: BACKGROUND: Zellweger syndrome (ZS) is a peroxisome biogenesis disorder due to mutations in any one of 13 PEX genes. Increased incidence of ZS has been suspected in French-Canadians of the Saguenay-Lac-St-Jean region (SLSJ) of Quebec, but this remains unsolved. METHODS: We identified 5 ZS patients from SLSJ diagnosed by peroxisome dysfunction between 1990--2010 and sequenced all coding exons of known PEX genes in one patient using Next Generation Sequencing (NGS) for diagnostic confirmation. RESULTS: A homozygous mutation (c.802_815del, p.[Val207_Gln294del, Val76_Gln294del]) in PEX6 was identified and then shown in 4 other patients. Parental heterozygosity was confirmed in all. Incidence of ZS was estimated to 1 in 12,191 live births, with a carrier frequency of 1 in 55. In addition, we present data suggesting that this mutation abolishes a SF2/ASF splice enhancer binding site, resulting in the use of two alternative cryptic donor splice sites and predicted to encode an internally deleted in-frame protein. CONCLUSION: We report increased incidence of ZS in French-Canadians of SLSJ caused by a PEX6 founder mutation. To our knowledge, this is the highest reported incidence of ZS worldwide. These findings have implications for carrier screening and support the utility of NGS for molecular confirmation of peroxisomal disorders.     

From skin allograft coverage to allograft–micrograft sandwich method: A retrospective review of severe burn patients who received conjunctive application of cultured epithelial autografts

A 12-year retrospective review of severe burn patients who received cultured epithelial autografts (CEA) at the Singapore General Hospital Burns Centre from January 2005 to December 2016 was carried out. During this period, two different surgical modalities were employed to manage these burn injuries. In the earlier period, following early excision of the burn wounds, exposed surfaces were covered with a combination of split thickness skin autografts (STSG) and allografts. Surfaces covered with skin allografts were subsequently debrided of the allo-epidermis in about 3 weeks later, exposing the allodermis with granulating tissues for grafting of CEA; a technique known as the Cuono’s method. In the later period, allograft–autologous micrograft sandwich technique was used to graft on the early excised burns with subsequent CEA grafting. The former and latter groups represented by STSG/C (n = 10) and M/CEA (n = 14) respectively, were compared in terms of clinical profiles, outcomes, allograft/CEA usage and total graft cost. No significant differences were found based on mean age and presence of inhalation burns between the two treatment methods However, percentage total body surface area (TBSA) and Revised Baux Score were significantly higher (p < 0.05) in the M/CEA group compared to the STSG/C group. Differences in clinical outcomes of mortality and length of hospital stay between the 2 groups were statistically insignificant. The average area amount of skin allografts used per patient in the M/CEA group was significantly lower compared to the STSG/C method group which contributed to lower total average cost of grafts used per % TBSA in the M/CEA method group. This might be attributed to the presence of micrografts which seemed to improve stabilization of the wound bed resulting in less operating procedures and improving CEA take. To conclude, the M/CEA method introduced was able to treat more severe burn patients at lower graft costs without compromising critical clinical outcomes significantly.     

Structure and strength of the distal radius in female patients with rheumatoid arthritis: A case‐control study

The purpose of this work was to investigate the volumetric bone mineral density (vBMD), bone microstructure, and mechanical indices of the distal radius in female patients with rheumatoid arthritis (RA). We report a cross‐sectional study of 66 middle‐aged female RA patients and 66 age‐matched healthy females. Areal BMD (aBMD) of the hip, lumbar spine, and distal radius was measured by dual‐energy X‐ray absorptiometry (DXA). High‐resolution peripheral quantitative computed tomography (HR‐pQCT) was performed at the distal radius, yielding vBMD, bone microstructure, and mechanical indices. Cortical and trabecular vBMD were 3.5% and 10.7% lower, respectively, in RA patients than controls, despite comparable aBMD. Trabecular microstructural indices were –5.7% to –23.1% inferior, respectively, in RA patients compared to controls, with significant differences in trabecular bone volume fraction, separation, inhomogeneity, and structural model index. Cortical porosity volume and percentage were 128% and 93% higher, respectively, in RA patients, with stress being distributed more unevenly. Fourteen RA patients had exaggerated periosteal bone apposition primarily affecting the ulnovolar aspect of the distal radius. These particular patients were more likely to have chronic and severe disease and coexisting wrist deformity. The majority of the differences in density and microstructure between RA patients and controls did not depend on menstrual status. Recent exposure to glucocorticoids did not significantly affect bone density and microstructure. HR‐pQCT provides new insight into inflammation‐associated bone fragility in RA. It detects differences in vBMD, bone microstructure, and mechanical indices that are not captured by DXA. At the distal radius, deterioration in density and microstructure in RA patients involved both cortical and trabecular compartments. Excessive bone resorption appears to affect cortical more than trabecular bone at distal radius, particularly manifested as increased cortical porosity. Ulnovolar periosteal apposition of the distal radius is a feature of chronic, severe RA with wrist deformity. © 2013 American Society for Bone and Mineral Research.     

Which women develop urgency or urgency urinary incontinence following midurethral slings?

Introduction and hypothesis

De novo urgency has a negative impact on women after midurethral sling (MUS). We aimed to identify risk factors for de novo urgency (dU) and urgency urinary incontinence (dUUI) following MUS, using multivariate analysis.

Methods

We investigated 358 consecutive women with only stress urinary incontinence (SUI) [or urodynamic stress incontinence (USI)] and 598 women with both SUI (or USI) and urgency (but not UUI) who underwent MUS with a mean follow-up of 50 months. Women who developed dU or dUUI at long-term follow-up were compared to those who did not.

Results

dU occurred in 27.7 % (99/358) and dUUI occurred in 13.7 % (82/598) of women at long-term follow-up after midurethral sling. Intrinsic sphincter deficiency {odds ratio (OR) dU 3.94 [95 % confidence interval (CI) 1.50–10.38]; OR dUUI 2.5 (1.31–4.80)}, previous stress incontinence surgery [sling: OR dU 3.69 (1.45–9.37); colposuspension: OR dUUI 2.5 (1.23–5.07)], previous prolapse surgery [OR dU 2.45 (1.18–5.10)], preexisting detrusor overactivity [OR dU 1.99 (1.15–3.48); OR dUUI 1.85 (1.31–2.60)] increased the risk, whereas performing concomitant apical prolapse surgery [OR dU 0.5 (0.41–0.81); OR dUUI 0.29 (0.087–0.97)] significantly decreased the risk. Women are more likely to not recommend surgery when they experienced dU (18.2 vs 0.8 %, p?<?0.0001) or dUUI (20.7 vs 2.1 %, p?<?0.0001).

Conclusions

Urodynamic parameters, history of prior incontinence or prolapse surgery and concomitant apical prolapse operation were important predictors of dU or dUUI following MUS.