The effect of substrate stiffness on adult neural stem cell behavior

Adult stem cells reside in unique niches that provide vital cues for their survival, self-renewal and differentiation. In order to better understand the contribution of substrate stiffness to neural stem/progenitor cell (NSPC) differentiation and proliferation, a photopolymerizable methacrylamide chitosan (MAC) biomaterial was developed. Photopolymerizable MAC is particularly compelling for the study of the central nervous system stem cell niche because Young's elastic modulus (E_Y) can be tuned from less than 1 kPa to greater than 30 kPa. Additionally, the numerous free amine functional groups enable inclusion of biochemical signaling molecules that, together with the mechanical environment, influence cell behavior. Herein, NSPCs proliferated on MAC substrates with Young's elastic moduli below 10 kPa and exhibited maximal proliferation on 3.5 kPa surfaces. Neuronal differentiation was favored on the softest surfaces with E_Y < 1 kPa as confirmed by both immunohistochemistry and qRT-PCR. Oligodendrocyte differentiation was favored on stiffer scaffolds (>7 kPa); however, myelin oligodendrocyte glycoprotein (MOG) gene expression suggested that oligodendrocyte maturation and myelination was best on <1 kPa scaffolds where more mature neurons were present. Astrocyte differentiation was only observed on <1 and 3.5 kPa surfaces and represented less than 2% of the total cell population. This work demonstrates the importance of substrate stiffness to the proliferation and differentiation of adult NSPCs and highlights the importance of mechanical properties to the success of scaffolds designed to engineer central nervous system tissue.     

Characterization of the p67phox gene: genomic organization and restriction fragment length polymorphism analysis for prenatal diagnosis in chronic granulomatous disease

The genetic defect in the p67phox-deficient form of chronic granulomatous disease (CGD) follows an autosomal recessive pattern of inheritance. When genomic DNA from normal individuals is digested with HindIII and probed with p67phox cDNA an allelic restriction fragment length polymorphism (RFLP) of 4.0 kb or 2.3 kb is detected. We cloned and characterized the p67phox gene using the cDNA and sequenced the exon/intron boundaries, mapping 16 exons on the 40-kb gene. The polymorphic region was then sequenced to identify the inheritance pattern of amniocentesis-derived fetal cells by genomic amplification. The proband, a 9-year-old female patient with p67phox-deficient CGD, and her phenotypically normal mother are homozygous for the RFLP marker, whereas the father and two brothers are heterozygous. The fetus was shown to be heterozygous as well, showing it had inherited at least one normal p67phox gene from the father and that it was predicted to have a normal phenotype. Cord blood samples at birth showed normal oxidative function. Amplification allows rapid detection of the inheritance pattern for fetal diagnosis in informative families. We report the genomic structure of p67phox and an amplification-based method for detection of the marker on chromosome 1q25, used here for prenatal diagnosis of CGD.     

Concomitant fractures of the capitellum and trochlea

A unique case of a coexistent fracture of the capitellum and trochlea is presented. The mechanism of injury and treatment options are reviewed.     

PRE-HOSPITAL EMERGENCY CARE: EVALUATION OF AN AUSTRALIAN SYSTEM

The efficacy of the Sydney ambulance paramedic service in dealing with out-of-hospital cardiac and other emergencies was examined. The outcome of 182 cases (from a total of 1,799 casualty calls) treated by a paramedic service was compared with the outcome of 104 similar cases (from a total of 2,376 calls) treated by a general duties service. There were 33 cases of cardiac arrest in the general duties group; resuscitation was attempted in 12 and none survived. There were 49 cases of cardiac arrest in the paramedic group; resuscitation was attempted in 21 cases and 4 survived. There were 35 cases of suspected myocardial infarction in the general duties group; 7 died compared with 58 cases and 4 deaths, in the paramedic group (mortality 20%, cf. 7%; difference not significant). The increased cost of a paramedic call, less than half of an entire hospital day, appears justified by better results.     

Childhood Pityriasis Rosea

Abstract: Pityriasis rosea (PR) is an acute, self‐limiting papulosquamous disorder of unknown etiology. Published studies of childhood PR are scarce and most are reviews. The aim of this study was to determine the demographic and clinical features of childhood PR.     

Neurological and adrenal dysfunction in the adrenal insufficiency/alacrima/achalasia (3A) syndrome

Review of 20 patients with glucocorticoid deficiency (three cases also with salt loss) associated with absent tear secretion (19 cases) and achalasia of the cardia (15 cases) revealed neurological abnormalities in 17 including hyper-reflexia, muscle weakness, dysarthria, and ataxia together with impaired intelligence and abnormal autonomic function, particularly postural hypotension. These findings indicate that significant neurological problems are common in this multisystem disorder.     

The tortuous or kinked carotid artery: pathogenesis and clinical considerations. A historical review

The significance and management of cervical carotid artery tortuosity are controversial. One hundred eighteen cases of angulation of the common carotid artery and over 800 cases of elongation of the internal carotid artery have been reported. The etiology, presentation, diagnosis, and treatment of each entity are reviewed. Angulation of the common carotid artery is often managed conservatively. For clarity, elongations of the internal carotid artery should be classified as either tortuosities or kinks. Some patients with kinks of the internal carotid artery will have episodes of cerebrovascular insufficiency related to the position of their heads. Such patients merit thorough diagnostic evaluation. When other etiologic factors have been eliminated, patients in this group may benefit from a surgical procedure directed at the vascular abnormality. Applicable surgical techniques are discussed.