Specific Subpopulations (specific + subpopulation)

Distribution by Scientific Domains


Selected Abstracts


Stoichiometry of lipid interactions with transmembrane proteins,Deduced from the 3D structures

PROTEIN SCIENCE, Issue 5 2006
Tibor Páli
Abstract The stoichiometry of the first shell of lipids interacting with a transmembrane protein is defined operationally by the population of spin-labeled lipid chains whose motion is restricted directly by the protein. Interaction stoichiometries have been determined experimentally for a wide range of ,-helical integral membrane proteins by using spin-label ESR spectroscopy. Here, we determine the spatially defined number of first-shell lipids at the hydrophobic perimeter of integral membrane proteins whose 3D structure has been determined by X-ray crystallography and lipid,protein interactions characterized by spin-labeling. Molecular modeling is used to build a single shell of lipids surrounding transmembrane structures derived from the PDB. Constrained energy optimization of the protein,lipid assemblies is performed by molecular mechanics. For relatively small proteins (up to 7,12 transmembrane helices), the geometrical first shell corresponds to that defined experimentally by perturbation of the lipid-chain dynamics. For larger, multi-subunit ,-helical proteins, the lipids perturbed directly by the protein may either exceed or be less in number than those that can be accommodated at the intramembranous perimeter. In these latter cases, the motionally restricted spin-labeled lipids can be augmented by intercalation, or can correspond to a specific subpopulation at the protein interface, respectively. For monomeric ,-barrel proteins, the geometrical lipid stoichiometry corresponds to that determined from lipid mobility for a 22-stranded barrel, but fewer lipids are motionally restricted than can be accommodated around an eight-stranded barrel. Deviations from the geometrical first shell, in the ,-barrel case, are for the smaller protein with a highly curved barrel. [source]


Oral health conditions of community-dwelling cognitively intact elderly persons with disabilities

GERODONTOLOGY, Issue 2 2007
Ralph Saunders
Objectives:, To present descriptive information on oral health and health care of community-dwelling elderly persons with disabilities who are living at home. Background:, Most previous studies have focused on specific subpopulations, namely, persons who are essentially healthy and independent, are homebound, or are nursing home residents. Little information appears to be available on community-residing elderly persons with disabilities. Materials and methods:, A total of 641 participants aged 65 years and over in a Medicare Demonstration who were cognitively intact, completed an oral health questionnaire within 1 year of Demonstration entry. Demonstration participants were required to be living in the community, need or receive help with 2+ activities of daily living (ADLs) or 3+ instrumental ADLs (IADLs), and have recently experienced significant health services utilisation. Results:, Subject mean age was 79.1 years, 73.8% were female, and 4% were minority. They were dependent in a mean of 1.8 ADLs and 2.9 IADLs. 43.1% reported that they had no natural teeth, 77.4% had dentures, 58.8% frequently felt their mouth was dry, 5.2% had jaw pain now and 6.1% had at some time experienced burning sensations in their mouth or tongue. 40.4% reported that they were currently in need of dental treatment, although 56.2% indicated they now had a dentist, and 42.1% identified having a dental visit within the past 12 months. 19.7% indicated some dental insurance coverage. Conclusion:, This is one of the first studies to focus on community-dwelling elderly people with disabilities. Substantial oral health morbidity was reported. [source]


Optimum survey methods when interviewing employed women

AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 2 2009
Kari Dunning PhD
Abstract Background While survey studies have examined bias much is unknown regarding specific subpopulations, especially women workers. Methods A population based phone, Internet, and mail survey of workplace falls during pregnancy was undertaken. Participation by industry and occupation and survey approach and bias, reliability, and incomplete data were examined. Results Of the 3,997 women surveyed, 71% were employed during their pregnancy. Internet responders were most likely to be employed while pregnant and to report a workplace fall at 8.8% compared to 5.8% and 6.1% for mail and phone respondents. Internet responders had the most missing employment data with company name missing for 17.9% compared to 1.3% for phone responders. Mail surveys were best for recruiting those employed in eight of nine industries, and this was especially true for service occupations. Conclusions To decrease bias and increase participation, mixed approaches may be useful with particular attention for collecting occupational data. Am. J. Ind. Med. 52:105,112, 2009. © 2008 Wiley-Liss, Inc. [source]


Parvalbumin-, calbindin-, and calretinin-immunoreactive hippocampal interneuron density in autism

ACTA NEUROLOGICA SCANDINAVICA, Issue 2 2010
Y. A. Lawrence
Lawrence YA, Kemper TL, Bauman ML, Blatt GJ. Parvalbumin-, calbindin-, and calretinin-immunoreactive hippocampal interneuron density in autism. Acta Neurol Scand: 2010: 121: 99,108. © 2009 The Authors Journal compilation © 2009 Blackwell Munksgaard. Background ,, There has been a long-standing interest in the possible role of the hippocampus in autism and both postmortem brain and neuroimaging studies have documented varying abnormalities in this limbic system structure. Aims ,, This study investigates the density of subsets of hippocampal interneurons, immunostained with the calcium binding proteins, calbindin (CB), calretinin (CR) and parvalbumin (PV) to determine whether specific subpopulations of interneurons are impacted in autism. Materials and methods ,, Unbiased stereological techniques were used to quantify the neuronal density of these immunoreactive subpopulations of gamma-aminobutyric acid-ergic (GABAergic) interneurons analyzed in the CA and subicular fields in postmortem brain material obtained from five autistic and five age-, gender- and postmortem interval-matched control cases. Results ,, Results indicate a selective increase in the density of CB-immunoreactive interneurons in the dentate gyrus, an increase in CR-immunoreactive interneurons in area CA1, and an increase in PV-immunoreactive interneurons in areas CA1 and CA3 in the hippocampus of individuals with autism when compared with controls. Discussion/conclusions ,, Although our sample size is small, these findings suggest that GABAergic interneurons may represent a vulnerable target in the brains of individuals with autism, potentially impacting upon their key role in learning and information processing. These preliminary findings further suggest the need for future more expanded studies in a larger number of postmortem brain samples from cases of autism and controls. [source]