Improved retroviral transfer of genes into canine hematopoietic progenitor cells kept in long-term marrow culture

Amphotropic helper-free retroviral vectors containing either the bacterial neomycin phosphotransferase gene (NEO) or a mutant dihydrofolate reductase gene (DHFR*) were used to infect canine hematopoietic progenitor cells. In previous experiments, successful transfer and expression of both genes in canine CFU-GM were achieved after 24-hour cocultivation with virus-producing cells. The average rate of gene expression was 10% (6% to 16%) as measured by the number of CFU-GM resistant to either the aminoglycoside G418 or methotrexate. In an attempt to increase the efficiency of gene transfer, marrow was cocultured for 24 hours with either NEO or DHFR* virus-producing packaging cells and then kept in long-term marrow culture fed three times with virus-containing supernatant (2 to 5 x 10(6) CFU/mL). After six days, cells were harvested and cultured in CFU-GM assay with and without a selective agent. The average rate of gene expression in CFU- GM in five independent experiments was 46% and ranged from 19% to 87%. In conclusion, the efficiency of gene transfer into canine hematopoietic progenitor cells has been increased fourfold by combining cocultivation with long-term marrow culture as compared with results obtained with cocultivation only.     

Cervical wear and occlusal wear from a periodontal perspective

Summary The aim of this study was to investigate whether cervical wear was associated with occlusal wear and clinical periodontal parameters in relatively older adults. A total of 30 patients, with multiple non‐carious cervical lesions (NCCLs) and without a disease or condition that could cause heavy tooth wear, were included in the study. The periodontal parameters including plaque index, probing pocket depth, gingival recession (GR) and tooth mobility were obtained from 641 teeth of which 475 (74·1%) displayed NCCLs. The levels of cervical wear and occlusal wear were determined according to a tooth wear index. Premolars were more likely to develop cervical wear than canines, molars and incisors. Cervical wear was significantly associated with less plaque accumulation and the presence of shallow pockets. The teeth with advanced GR and without increased mobility were 2·583 and 1·715 times more likely to develop deeper cervical lesions, respectively. Age and the level of occlusal wear were not linked to the bucco‐lingual depth of cervical wear. In conclusion, the significant association of advanced cervical wear with the relatively healthy periodontal status suggested the role of abrasion and its possible combined action with erosion in the aetiology of NCCLs. The rate of GR and the lack of tooth mobility could constitute predisposing factors for the progression of cervical wear because the exposed root surfaces could be more susceptible to abrasion and/or erosion, and the non‐mobile teeth resisting strongly against frictional forces, thus abrasive effects, could possibly develop cervical wear.     

Changes in social support and their impact on psychosocial outcome over a 5-year period for African American and White dementia caregivers

BACKGROUND: African Americans have been found to be more resilient to the caregiving role than Whites. Amount of social support and satisfaction with social support were studied as possible explanations for these racial differences. METHODS: Family caregivers of patients diagnosed as having dementia participated in a longitudinal study. There were 166 caregiver-patient dyads enrolled and annual follow-up assessments were completed. Linear random effects regression models examined the longitudinal trajectories of social support, depressive symptoms, and life satisfaction over 5 years of community follow-up. Social support was also included as a time-dependent predictor of depressive symptoms and life satisfaction. RESULTS: The number of helpful support persons available decreased significantly for both racial groups. African American caregivers reported more satisfaction with their social support networks than Whites. They also reported fewer depressive symptoms and higher levels of life satisfaction when compared to their White counterparts. Higher levels of satisfaction with social support were associated with fewer depressive symptoms and increased levels of life satisfaction and explained a portion of the racial differences on these measures of psychosocial outcome. CONCLUSIONS: The resilience of African American caregivers, as displayed by their fewer depressive symptoms and higher levels of life satisfaction, was partially explained by their higher levels of satisfaction with social support. Results suggest that health care providers should view low levels of social support as a possible precursor to poor psychological outcomes in caregivers. Future research should focus on social support and cultural variables that might explain racial differences in caregiver outcomes.