The structural and functional integrity of peripheral nerves depends on the glial-derived signal desert hedgehog

We show that desert hedgehog ( dhh), a signaling molecule expressed by Schwann cells, is essential for the structural and functional integrity of the peripheral nerve. Dhh-null nerves display multiple abnormalities that affect myelinating and nonmyelinating Schwann cells, axons, and vasculature and immune cells. Myelinated fibers of these mice have a significantly increased ( more than two times) number of Schmidt-Lanterman incisures ( SLIs), and connexin 29, a molecular component of SLIs, is strongly upregulated. Crossing dhh-null mice with myelin basic protein ( MBP)-deficient shiverer mice, which also have increased SLI numbers, results in further increased SLIs, suggesting that Dhh and MBP control SLIs by different mechanisms. Unmyelinated fibers are also affected, containing many fewer axons per Schwann cell in transverse profiles, whereas the total number of unmyelinated axons is reduced by approximately one-third. In dhh-null mice, the blood-nerve barrier is permeable and neutrophils and macrophage numbers are elevated, even in uninjured nerves. Dhh-null nerves also lack the largest-diameter myelinated fibers, have elevated numbers of degenerating myelinated axons, and contain regenerating fibers. Transected dhh nerves degenerate faster than wild-type controls. This demonstrates that a single identified glial signal, Dhh, plays a critical role in controlling the integrity of peripheral nervous tissue, in line with its critical role in nerve sheath development ( Parmantier et al., 1999). The complexity of the defects raises a number of important questions about the Dhh-dependent cell-cell signaling network in peripheral nerves

Enhancing Parent-Child Communication and Parental Self-Esteem With a Video-Feedback Intervention: Outcomes With Prelingual Deaf and Hard-of-Hearing Children

Evidence on best practice for optimizing communication with prelingual deaf and hard-of-hearing (DHH) children is lacking. This study examined the effect of a family-focused psychosocial video intervention program on parent–child communication in the context of childhood hearing loss. Fourteen hearing parents with a prelingual DHH child (Mage = 2 years 8 months) completed three sessions of video interaction guidance intervention. Families were assessed in spontaneous free play interactions at pre and postintervention using the Emotional Availability (EA) Scales. The Rosenberg Self-esteem Scale was also used to assess parental report of self-esteem. Compared with nontreatment baselines, increases were shown in the EA subscales: parental sensitivity, parental structuring, parental nonhostility, child responsiveness, and child involvement, and in reported self-esteem at postintervention. Video-feedback enhances communication in families with prelingual DHH children and encourages more connected parent–child interaction. The results raise implications regarding the focus of early intervention strategies for prelingual DHH children

The Great Naval Battle of North Point: Myth or Reality?

Hollywood itself could hardly have scripted a better battle. According to eyewitnesses, a German U-boat lurking off the shores of North Point, Prince Edward Island, laid a trap for an unsuspecting convoy transitting the Northumberland Strait. On 7 May 1943, the trap was sprung, Canadian naval escorts and aircraft did their best to defend the beleaguered convoy from a brazen and unorthodox attack that was unlike any other. There could only be one conclusion: the German commander was half-mad. Just like the fictional Captain Ahab, he was willing to take unwarranted risks with his boat and men to destroy his white whale that came in the form of a troop ship at the centre of the convoy. His obsession led to a stunning three hour engagement that was brought to a dramatic end as the Canadians scored a direct hit forcing the U-boat’s bow to rise sharply out of the water before sinking. The problem is that there is no evidence that this battle ever took place

The Canadian Role in Operation “Charnwood,” 8 July 1944: A Case Study in Tank/Infantry Doctrine and Practice

On the morning of 8 July 1944, soldiers of the 9th Canadian Infantry Brigade (9 CIB) left their startlines near the Norman village of Vieux Cairon heading for Buron and Gruchy; two villages nearly 2,000 yards across open ground to the south. Their advance was part of Operation “Charnwood,” British I Corps’ final assault on Caen. By the end of the day most objectives were secured, and on 9 July Caen north of the Orne River and Canal was captured. General Dempsey, General Officer Commanding (GOC) British 2nd Army expressed his satisfaction, saying that the operations of 8 and 9 July were “well and cleanly carried out.” Troops of the 3rd Canadian Infantry Division (3 CID) and the 2nd Canadian Armoured Brigade (2 CAB) shared in the victory no less than the British divisions that took part. “Charnwood” stands apart from other Canadian operations in Normandy because it was the only operation of its type undertaken by 3 CID and 2 CAB as complete formations. After “Charnwood” II Canadian Corps became operational, and the scale, tempo and expectations of operations altered considerably. The capture of Caen, therefore, affords insights into tactical doctrine that are obscured by later large-scale operations with more ambitious objectives. In particular, in this operation the Canadian armour and infantry defeated the Germans by employing tanks as direct-fire closesupport weapons. In fact, such intimate support had not been a part of Canadian tank/infantry doctrine since the introduction of the Sherman tank in 1943. Instead, since the fall of 1943 armoured units were told specifically to work to the enemy’s flanks and support by fire, not by participating in the close infantry battle. The fighting on 8 July indicates that in this instance at least, Canadian troops won in spite of the prevailing doctrine and not because of it

Post-school Transitions of People who are Deaf or Hard of Hearing:Appendices

The ongoing UK and European economic crisis is leading to a rapid growth in youth unemployment in Scotland. Young disabled people, including those who are deaf or hard of hearing, are more likely than others to experience difficulties in obtaining employment. Recognising the difficulties experienced by young disabled people in accessing post-school education, training and employment, the Scottish Government has attempted to put in place specific and generic support. This study aimed to investigate the post-16 transition process and outcomes of young people with hearing impairments and assess the nature of the support available to them and the barriers which they encounter.We have highlighted the wide range of post-school transition experiences and outcomes of young people who are deaf or hard of hearing. We have identified patterns of post-school transitions, and the ways these are strongly associated with socio-economic status and educational outcomes at school. Differences were found between those young people with higher levels of qualification who progress into higher education, those with somewhat lower levels of qualification who move into mainstream further education and training, and those with few or no qualifications who move into personal development programmes in college, or who become disengaged from education, training and employment

Language and Reading Progress of Young Deaf and Hard-of-Hearing Children.

We examined the language and reading progress of 336 young DHH children in kindergarten, first and second grades. Trained assessors tested children's language, reading, and spoken and fingerspelled phonological awareness in the fall and spring of the school year. Children were divided into groups based on their auditory access and classroom communication: a spoken-only group (n = 101), a sign-only group (n = 131), and a bimodal group (n = 104). Overall, children showed delays in language and reading compared to norms established for hearing children. For language, vocabulary standard scores were higher than for English syntax. Although delayed in language, children made expected gains based on hearing norms from kindergarten to second grade. Reading scores declined from kindergarten to second grade. Spoken-only and bimodal children had similar word reading and reading comprehension abilities and higher scores than sign-only children. Spoken-only children had better spoken phonological awareness and nonword reading skills than the other two groups. The sign-only and bimodal groups made similar and significant gains in ASL syntax and fingerspelling phonological awareness

“For extraordinary heroism and outstanding performance”: Kay’yong, 2 PPCLI and the Controversy surrounding the US Presidential Unit Citation

Despite a growing historiography, the Canadian experience in Korea is still a very much forgotten part of our history. Kap’yong, the marathon battle of 22–25 April 1951 where the Second Battalion of the Princess Patricia’s Canadian Light Infantry (22PLCI) along with their fellow members of the 27th Commonwealth Infantry Brigade, the Third Battalion Royal Australian Regiment (3RAR) defended the access points of the Kap’yong River valley is the one incident receives significant attention. Without fail, the description of the battle always ends with that passing reference, “for their efforts 2PPCLI were awarded the United States Presidential Unit Citation.” This brief sentence at the end of a chapter does little to define the citation let alone explore its journey from recommendation to its place as a device on the uniforms of members of 2PPCLI. While the battle itself was epic in the context of Korea, the story of the Presidential Unit Citation was not without its own lengthy ordeal. The award was first recommended in the spring of 1951. However, the Canadian government did not officially announce that members of the Battalion would be able to wear the individual insignia of the citation until April 1956, a period of some five years