Effects of education on very mild dementia among Chinese people in Hong Kong: Potential mediators in the Cantonese Mini-Mental State Examination tasks

Background: In Hong Kong, older Chinese adults generally have a low level of education. This study examined the effect of education on very mild Alzheimer's disease (AD), as quantified by Clinical Dementia Rating (CDR) scale (CDR 0.5 versus 0), in a Chinese community. The Cantonese version of the Mini-Mental State Examination (C-MMSE) was used to estimate cognitive abilities that were related to the level of education, and that in turn serve as protective factors for AD.

Methods: A total of 788 community-dwelling older adults (383 CDR 0 and 405 CDR 0.5) were recruited in this cross-sectional study, which was derived from a population-based prevalence project. The participants’ number of years of education and C-MMSE scores were used to predict their CDR scores using logistic regression and the mediation effects of C-MMSE scores were analyzed.

Results: Consistent with previous studies, the chance of being rated as having very mild AD increased with age, but decreased with years of education, among the older adult community of Hong Kong. The effect of education on very mild dementia was weakened substantially when C-MMSE scores were included as mediating variables.

Conclusions: The findings indicate that the protective effects of education on dementia were mediated by an enhancement of older adults’ performance on some C-MMSE items, including attention and orientation to time and place.     

Prospective study of one- vs two-unit umbilical cord blood transplantation following reduced intensity conditioning in adults with hematological malignancies

As the threshold nucleated cell dose for one-unit umbilical cord blood (UCB) in adults has not to date been firmly established, we prospectively compared one- vs two-unit UCB transplantation after reduced intensity conditioning (RIC) in adult patients with hematological malignancies. Study design specified one-UCB unit if the cryopreserved total nucleated cell (TNC) dose was 2.5 × 10(7)/kg recipient weight, otherwise two units matched at minima of 4/6 HLA loci to the patient and 3/6 to each other were infused. A total of 27 patients received one unit; 23 patients received two units. Median time to ANC >500/μL was 24 days (95% confidence interval 22-28 days), 25 days for one unit and 23 days for two units (P=0.99). At day 100, ANC >500/μL was 88.4 and 91.3% in the one- and two-unit groups (P=0.99), respectively. Three-year EFS was 28.6% and 39.1% in the one- and two-unit groups (P=0.71), respectively. Infusion of two units was associated with a significantly lower relapse risk, 30.4% vs 59.3% (P=0.045). Infused cell doses (TNC, CD3(+), CD34(+) and CD56(+)CD3(neg)) did not impact on engraftment, OS or EFS. Taken together, one-unit UCB transplantation with a threshold cell dose 2.5 × 10(7)/kg recipient weight after RIC is a viable option for adults, although infusion of two units confers a lower relapse incidence.     

Type II enteropathy-associated T-cell lymphoma: a multicenter analysis from the Asia Lymphoma Study Group

Enteropathy‐associated T‐cell lymphoma (EATL) is a rare primary gastrointestinal T‐cell lymphoma. A multicenter study from the Asia Lymphoma Study Group identified 38 EATL patients within a 19‐year period. All cases were type II EATL. Men were affected twice as common as women, at a median age of 59 (23–89) years. None had a history of celiac disease. The sites of involvement were small bowel and stomach (5%), small bowel (63%), small and large bowel (16%), and large bowel (18%). Common presenting features were bowel perforation (34%), pain (32%), and obstruction (21%). Lymphomas showed monomorphic neoplastic lymphoid infiltrates that were CD3⁺ (100%), CD56⁺ (91%), TIA‐1⁺ (96%), CD4^–CD8⁺ (63%), CD4⁺CD8⁺ (19%), CD4^–CD8^– (16%), and CD4⁺CD8^– (3%). Epstein Barr virus was demonstrable in three cases. Despite chemotherapy and/or surgical resection, the overall response and complete response rates were poor at 46% and 38%. The median overall survival (OS) was 7 months and progression‐free‐survival (PFS) 1 month. Five patients underwent hematopoietic stem cell transplantation all were alive. Age and the prognostic index for peripheral T‐cell lymphoma were not prognostically significant. Good performance status was associated with better OS (P = 0.03), and response to initial treatment led to better OS and PFS (P < 0.001). Am. J. Hematol. 87:663–668, 2012. © 2012 Wiley Periodicals, Inc.     

Neural mechanisms of feature conjunction learning: Enduring changes in occipital cortex after a week of training

Most visual activities, whether reading, driving, or playing video games, require rapid detection and identification of learned patterns defined by arbitrary conjunctions of visual features. Initially, such detection is slow and inefficient, but it can become fast and efficient with training. To determine how the brain learns to process conjunctions of visual features efficiently, we trained participants over eight consecutive days to search for a target defined by an arbitrary conjunction of color and location among distractors with a different conjunction of the same features. During each training session, we measured brain activity with functional magnetic resonance imaging (fMRI). The speed of visual search for feature conjunctions improved dramatically within just a few days. These behavioral improvements were correlated with increased neural responses to the stimuli in visual cortex. This suggests that changes in neural processing in visual cortex contribute to the speeding up of visual feature conjunction search. We find evidence that this effect is driven by an increase in the signal‐to‐noise ratio (SNR) of the BOLD signal for search targets over distractors. In a control condition where target and distractor identities were exchanged after training, learned search efficiency was abolished, suggesting that the primary improvement was perceptual learning for the search stimuli, not task‐learning. Moreover, when participants were retested on the original task after nine months without further training, the acquired changes in behavior and brain activity were still present, showing that this can be an enduring form of learning and neural reorganization. Hum Brain Mapp 35:1201–1211, 2014. © 2013 Wiley Periodicals, Inc.