Evidence for clinical,genetic and biochemical variability in spinal muscular atrophy with progressive myoclonic epilepsy

Spinal muscular atrophy with progressive myoclonic epilepsy (SMA‐PME) is a recently delineated, autosomal recessive condition caused by rare mutations in the N‐acylsphingosine amidohydrolase 1 (acid ceramidase) ASAH1 gene. It is characterized by motor neuron disease followed by progressive myoclonic seizures and eventual death due to respiratory insufficiency. Here we report an adolescent female who presented with atonic and absence seizures and myoclonic jerks and was later diagnosed as having myoclonic‐absence seizures. An extensive genetic and metabolic work‐up was unable to arrive at a molecular diagnosis. Whole exome sequencing (WES) identified two rare, deleterious mutations in the ASAH1 gene: c.850G>T;p.Gly284X and c.456A>C;p.Lys152Asn. These mutations were confirmed by Sanger sequencing in the patient and her parents. Functional studies in cultured fibroblasts showed that acid ceramidase was reduced in both overall amount and enzymatic activity. Ceramide level was doubled in the patient's fibroblasts as compared to control cells. The results of the WES and the functional studies prompted an electromyography (EMG) study that showed evidence of motor neuron disease despite only mild proximal muscle weakness. These findings expand the phenotypic spectrum of SMA‐PME caused by novel mutations in ASAH1 and highlight the clinical utility of WES for rare, intractable forms of epilepsy.     

The role of epithelial injury and repair in the origins of asthma

PURPOSE OF REVIEW: We currently understand little about the mechanisms that lead to asthma. The bronchial epithelium is the first cell layer of contact with the environment and as such is an especially attractive target in which to identify novel mechanisms and new therapeutic strategies in disease development. We discuss the role of epithelial injury and wound repair in the origins of asthma. RECENT FINDINGS: The presence of inflammation, thickening of the basement membrane and angiogenesis have been described in bronchial biopsies from asthmatic children. We and others have demonstrated the utility of bronchial brushings from children for the isolation, characterization and culture of primary epithelial cells. The results of these experiments suggest that intrinsic differences exist between asthmatic and nonasthmatic epithelial cells. SUMMARY: It is becoming increasingly clear from studies involving adults and, more recently, children, that the epithelium orchestrates inflammatory and remodeling responses of the airway. Equally clear is that the asthmatic epithelium responds inappropriately to challenge and displays signs of dysregulated repair. Understanding the regulatory mechanisms involved in these processes, including the role of resident/recruited progenitor cells, is crucial if we are to halt the progression of asthma when the disease first manifests in childhood.     

Endotoxemia increases the clearance of mPEGylated 5000-MW quantum dots as revealed by multiphoton microvascular imaging

Imaging the microcirculation is becoming increasingly important in assessing life-threatening disease states. To address this issue in a highly light absorbing and light scattering tissue, we use laser scanning multiphoton microscopy and fluorescent 655-nm 5000-MW methoxy-PEGylated quantum dots to image the functional microcirculation deep in mouse hind limb skeletal muscle. Using this approach, we are able to minimize in vivo background tissue autofluorescence and visualize complete 3-D microvascular units, including feeding arterioles, capillary networks, and collecting venules to depths of 150 to 200 microm. In CD1 mice treated with lipopolysaccharide to model an endotoxemic response to bacterial infection, we find that these quantum dots accumulate at microvascular bifurcations and extravasate from the microcirculation in addition to accumulating in organs (liver, spleen, lung, and kidney). The quantum dots are cleared from the circulation with a first-order elimination rate constant seven times greater than under normal conditions, 1.6+/-0.06 compared to 0.23+/-0.05 h(-1), P<0.05, thereby reducing the imaging time window. In vitro experiments using TNFalpha treated isolated leukocytes suggest that circulating monocytes (phagocytes) increased their nonspecific uptake of quantum dots when activated. In combination with multiphoton microscopy, quantum dots provide excellent in vivo imaging contrast of deep microvascular structures.     

Gentamicin in neonates at risk for sepsis – peak serum concentrations are not necessary

BACKGROUND:

Serum gentamicin concentrations (GSCs) are frequently obtained before and after gentamicin administration to newborns with, or at high risk for, sepsis.

OBJECTIVE:

To determine whether performing a peak GSC assay when the trough GSC is within the guidelines for care would add clinically relevant information for health care workers.

METHODS:

A retrospective review of the IWK Health Centre (Halifax, Nova Scotia) laboratory database for peak and trough GSC for infants <28 days after birth was performed.

RESULTS:

Of 5253 paired samples of trough and peak GSCs, 3001 (57%) had trough GSCs ≤2 μg/mL. Of these, only nine (0.3%) had a peak GSC >10 μg/mL.

CONCLUSIONS:

Performing a peak GSC measurement does not provide further clinically important data and increases patient morbidity and hospital costs.     

婴幼儿胃食管反流相关性咳嗽治疗的初步研究

目的婴幼儿哮喘的诊断主要基于咳嗽及喘息等临床症状,神经系统功能正常的婴幼儿当出现过度胃食管反流时也可以出现类似症状。目前并无随机对照研究来评价单独使用质子泵抑制剂或联合促动力药在婴幼儿中应用的疗效。本研究的主要目的是证实在呼吸道症状提示哮喘的婴幼儿中的确存在过度胃食管反流。其次,通过随机空白对照试验,探讨使用氨基甲酰甲基胆碱和奥美拉唑治疗过度胃食管反流可否改善呼吸道症状。方法有慢性咳嗽或喘息病史且有病史支持、pH监测异常或胃排空扫描提示胃食管反流的婴幼儿22例,随机分为4个治疗组:安慰剂+安慰剂(PP治疗组)、奥美拉唑+氨基甲酰甲基胆碱(OB治疗组)、奥美拉唑+安慰剂(OP治疗组)、氨基甲酰甲基胆碱+安慰剂(BP治疗组)。通过临床问卷调查、检查和家庭日记以及pH监测数据评估患儿上述治疗前后及奥美拉唑+氨基甲酰甲基胆碱非盲试验后的情况。结果 19例纳入数据统计。PP治疗对胃食管反流或呼吸道症状没有作用,pH监测提示胃食管反流并无减少。然而根据pH监测及家长评估,OB治疗可减少胃食管反流,同时显著减少日间咳嗽,改善呼吸,无不良反应发生。结论对于临床表现提示慢性胃食管反流相关性咳嗽的婴幼儿,使用奥美拉唑和氨基甲酰甲基胆碱治疗是可行的选择。     

Susceptibility of cyclooxygenase-2-deficient mice to pulmonary fibrogenesis

The cyclooxygenase (COX)-2 enzyme has been implicated as an important mediator of pulmonary fibrosis. In this study, the lung fibrotic responses were investigated in COX-1 or COX-2-deficient (-/-) mice following vanadium pentoxide (V(2)O(5)) exposure. Lung histology was normal in saline-instilled wild-type and COX-deficient mice. COX-2(-/-), but not COX-1(-/-) or wild-type mice, exhibited severe inflammatory responses by 3 days following V(2)O(5) exposure and developed pulmonary fibrosis 2 weeks post-V(2)O(5) exposure. Western blot analysis and immunohistochemistry showed that COX-1 protein was present in type 2 epithelial cells, bronchial epithelial cells, and airway smooth muscle cells of saline or V(2)O(5)-exposed wild-type and COX-2(-/-) mice. COX-2 protein was present in Clara cells of wild-type and COX-1(-/-) terminal bronchioles and was strongly induced 24 hours after V(2)O(5) exposure. Prostaglandin (PG) E(2) levels in the bronchoalveolar lavage (BAL) fluid from wild-type and COX-1(-/-) mice were significantly up-regulated by V(2)O(5) exposure within 24 hours, whereas PGE(2) was not up-regulated in COX-2(-/-) BAL fluid. Tumor necrosis factor-alpha was elevated in the BAL fluid from all genotypes after V(2)O(5) exposure, but was significantly and chronically elevated in the BAL fluid from COX-2(-/-) mice above wild-type or COX-1(-/-) mice. These findings indicate that the COX-2 enzyme is protective against pulmonary fibrogenesis, and we suggest that COX-2 generation of PGE(2) is an important factor in resolving inflammation.     

Poly(dimethylsiloxane) thin films as biocompatible coatings for microfluidic devices: cell culture and flow studies with glial cells

Oxygen plasma treatment of poly(dimethylsiloxane) (PDMS) thin films produced a hydrophilic surface that was biocompatible and resistant to biofouling in microfluidic studies. Thin film coatings of PDMS were previously developed to provide protection for semiconductor-based microoptical devices from rapid degradation by biofluids. However, the hydrophobic surface of native PDMS induced rapid clogging of microfluidic channels with glial cells. To evaluate the various issues of surface hydrophobicity and chemistry on material biocompatibility, we tested both native and oxidized PDMS (ox-PDMS) coatings as well as bare silicon and hydrophobic alkane and hydrophilic oligoethylene glycol silane monolayer coated under both cell culture and microfluidic studies. For the culture studies, the observed trend was that the hydrophilic surfaces supported cell adhesion and growth, whereas the hydrophobic ones were inhibitive. However, for the fluidic studies, a glass-silicon microfluidic device coated with the hydrophilic ox-PDMS had an unperturbed flow rate over 14 min of operation, whereas the uncoated device suffered a loss in rate of 12%, and the native PDMS coating showed a loss of nearly 40%. Possible protein modification of the surfaces from the culture medium also were examined with adsorbed films of albumin, collagen, and fibrinogen to evaluate their effect on cell adhesion.