Improved quantification of amyloid burden and associated biomarker cut-off points: results from the first amyloid Singaporean cohort with overlapping cerebrovascular disease

European Journal of Nuclear Medicine and Molecular Imaging - The analysis of the [11C]PiB-PET amyloid images of a unique Asian cohort of 186 participants featuring overlapping vascular diseases...     

Osteochondral repair using an acellular dermal matrix—pilot in vivo study in a rabbit osteochondral defect model

The aim of this pilot project was to introduce a novel use of acellular dermal matrix (ADM) in combination with infrapatellar fat pad mesenchymal stromal cells (IPFP‐MSCs) to effect repair in a rabbit osteochondral defect model. ADM, in a range of surgical procedures, has been shown to promote remodelling of tissue at the site of implantation. Rabbit‐derived ADM (rabADM) was prepared from the skin of donor rabbits. Autologous IPFP‐MSCs were obtained at the time of knee surgery. Osteochondral defects (4 mm cartilage outer/2 mm central bone defect) were drilled into distal femoral condyles of 12 New Zealand White rabbits. Treatments groups: (i) defect only; (ii) rabADM alone; (iii) IPFP‐MSCs alone; and (iv) rabADM with IPFP‐MSCs. Condyles were harvested at 12 weeks, and analyzed using histology, immunohistochemistry (types I and II collagen) and histomorphometry to evaluate osteochondral repair. The rabADM only group achieved the highest ratio of type II to non‐type II collagen (77.3%) using areal measures (similar to normal cartilage), which indicated a higher quality of cartilage repair. The addition of IPFP‐MSCs, with or without rabADM, formed a fibrous collagen cap above the lesion site not seen with rabADM alone. Macroscopically, there was no joint erosion, inflammation, swelling or deformity, and all animals maintained full range of motion. Conclusions: RabADM alone resulted in neocartilage formation similar to native cartilage. IPFP‐MSCs limited osteochondral repair and contributed to fibrosis, even in combination with the rabADM. Further studies using ADM for osteochondral repair are warranted in a more appropriate pre‐clinical model of osteochondral repair. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1919–1928, 2018.

     

Olfactory functions in asymptomatic carriers of the Huntington disease mutation

Huntington's disease (HD) is a neurodegenerative disorder initially affecting the basal ganglia and especially the head of the caudate nucleus. Neuropsychological research has indicated that olfactory dysfunction may appear early in HD, prior to the onset of significant motor or cognitive dysfunction. The aim of this study was to examine whether asymptomatic carriers of the Huntington disease mutation also exhibit olfactory dysfunction. To address this issue we presented an extensive olfactory test battery comprising tasks assessing olfactory sensitivity, intensity discrimination, quality discrimination, episodic odor memory, and odor identification, to a group of gene carriers and nonmutation carriers of the disease. The results showed that gene carriers were selectively impaired in discriminating odor quality, although performance did not differ from noncarriers across the other tasks. The role played by striatum and then in particular the caudate nucleus for olfactory processing in general, and for odor quality discrimination in particular, is discussed.     

Brief Report: Sex Differences in Parental Concerns for Toddlers with Autism Risk

Research on sex differences in autism spectrum disorder (ASD) suggests both higher prevalence and a more easily observable presentation of core ASD symptomology in males, which may lead to sex differences in parental concerns. The current study examined whether sex and diagnosis relate to the timing, number, and types of pre-diagnosis concerns for 669 (N_male = 468) toddlers who screened at risk for ASD. No sex differences in parents’ concerns emerged for toddlers diagnosed with ASD; however, in the overall at-risk sample, parents of boys endorsed ASD symptoms, including restricted and repetitive behaviors, more than parents of girls. Future research should examine why sex differences in pre-diagnosis concerns emerge and how they might impact early diagnosis for at-risk boys versus girls.     

Identifiability, exchangeability and confounding revisited

In 1986 the International Journal of Epidemiology published "Identifiability, Exchangeability and Epidemiological Confounding". We review the article from the perspective of a quarter century after it was first drafted and relate it to subsequent developments on confounding, ignorability, and collapsibility.     

“Marden-Walker Syndrome”: Neuropathologic Findings in Two Siblings

Neuropathologic examination of two siblings with phenotypic features consistent with Marden-Walker syndrome revealed central nervous system abnormalities which include reduction in the number of spinal anterior horn cells. The occurrence of these changes in a sibling pair provides strong evidence for a genetic etiology. The relationship between the neuropathologic changes and other phenotypic manifestations in this syndrome and in the closely related syndrome of Pena-Shokeir are discussed.     

Anesthetic management of acquired tracheoesophageal fistula: a brief report

IMPLICATIONS: Tracheoesophageal fistula may be either a congenital lesion or an acquired condition, most often resulting from foreign body ingestion. Location of the lesion has implications for anesthetic management and single lung ventilation may be required to facilitate surgical repair. In pediatric patients, intentional mainstem intubation may be required.