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Biomedical subjects

E S Sorensen

Publications and source records attributed to E S Sorensen.

12 recordsLinked to original sources
PubMed2000

The structure of the membrane-binding 38 C-terminal residues from bovine PP3 determined by liquid- and solid-state NMR spectroscopy.

The secondary structure and membrane-associated conformation of a synthetic peptide corresponding to the putative membrane-binding C-terminal 38 residues of the bovine milk component PP3 was determined using 1H NMR in methanol, CD in methanol and SDS micelles, and 15N solid-state NMR in planar phospholipid bilayers. The solution NMR and CD spectra reveal that the PP3 peptide in methanol and SDS predominantly adopts an alpha-helical conformation extending over its entire length with a potential bend around residue 19. 15N solid-state NMR of two PP3 peptides 15N-labelled at the Gly7 and Ala32 positions, respectively, and dissolved in dimyristoylphosphatidylcholine/dimyristoylphosphatidylglycerol phospholipid bilayers shows that the peptide is associated to the membrane surface with the amphipathic helix axis oriented parallel to the bilayer surface.

Amino Acid Sequence↗
PubMed1999

Biochemical evidence for heme linkage through esters with Asp-93 and Glu-241 in human eosinophil peroxidase. The ester with Asp-93 is only partially formed in vivo.

The covalent heme attachment has been extensively studied by spectroscopic methods in myeloperoxidase and lactoperoxidase (LPO) but not in eosinophil peroxidase (EPO). We show that heme linkage to the heavy chain is invariably present, whereas heme linkage to the light chain of EPO is present in less than one-third of EPO molecules. Mass analysis of isolated heme bispeptides supports the hypothesis of a heme b linked through two esters to the polypeptide. Mass analysis of heme monopeptides reveals that >90% have a nonderivatized methyl group at the position of the light chain linkage. Apparently, an ester had not been formed during biosynthesis. The light chain linkage could be formed by incubation with hydrogen peroxide, in accordance with a recent hypothesis of autocatalytic heme attachment based on studies with LPO (DePillis, G. D., Ozaki, S., Kuo, J. M., Maltby, D. A., and Ortiz de Montellano P. R. (1997) J. Biol. Chem. 272, 8857-8860). By sequence analysis of isolated heme peptides after aminolysis, we unambiguously identified the acidic residues, Asp-93 of the light chain and Glu-241 of the heavy chain, that form esters with the heme group. This is the first biochemical support for ester linkage to two specific residues in eosinophil peroxidase. From a parallel study with LPO, we show that Asp-125 and Glu-275 are engaged in ester linkage. The species with a nonderivatized methyl group was not found among LPO peptides.

Amino Acid Sequence↗
PubMed1997

An examination of the binding of aluminum to protein and mineral components of bone and teeth.

Aluminum binding by a variety of noncollagenous proteins associated with bone and teeth (osteopontin, osteocalcin and phosphophoryn) and by hydroxyapatite are examined. The proteins bound aluminum with a dissociation constant, KD, of the 10(-7) M or greater at pH = 7. The number of atoms of aluminum bound was found to be related to but not equivalent to the number of phosphorylated serines in osteopontin and phosphophoryn. Osteocalcin bound one aluminum tightly presumably due to its gamma-carboxyl glutamate residues. Hydroxyapatite bound Al3+ tightly releasing 1.5 equivalent Ca2+ per Al3+ bound. Addition of 3 mM Ca2+, close to the total concentration found in animal circulating fluids, did not effect noticeably the amount of Al3+ bound to bone which must have a KD for Al3+ < 10(-6). Silicic acid added after equilibration with all these materials has little effect but neither the proteins nor hydroxyapatite removed much Al3+ from pre-equilibrated Al3+ solution with silicic acid. The results are discussed with regard to Al3+ poisoning.

Aluminum↗
PubMed1994

Daily stressors and coping responses: a comparison of rural and suburban children.

Although research has examined problems of stress and health among rural families, little is known about coping phenomena directly from the perspective of rural children. This study compared two groups of children, one rural and the other suburban, in their reports of daily stressors and coping efforts as actually experienced. Using semistructured diaries over a period of six weeks, 21 rural children and 23 suburban children reported daily sources of stress, coping efforts, and coping resources. Rural children were more compliant in completing diaries. They reported more internal, cognitive-intrapsychic source of stress, whereas suburban children listed more external environmental sources. Suburban boys reported submission as the most common coping response, and rural boys listed organized activities and problem-solving approaches. Other interesting differences between the rural and suburban children, and gender differences among both groups emerged.

Adaptation, Psychological↗
PubMed1991

Home care of the elderly: a family perspective.

Family home care of the elderly has become a primary focus of nursing theory, practice, and research. Traditional study of home care of the elderly, particularly the cognitively impaired, has focused on the experience of the caregiver. There is a need for consideration of the perception of the care recipient and the entire family unit. A model to explain the characteristics of the elderly care recipient, as well as theoretic and methodologic implications, are offered.

Aged↗
PubMed1991

Identification of stress buffers in school-age children.

Dealing with stress has become an important issue in health education in community settings. With increasing demands and changes in the daily lives of families, helping children to deal with stress has become increasingly more significant in community health nursing. Nurses who want to mediate effects of stress in children need more information about stress buffers in the daily lives of children. This study attempted to identify and describe stress buffers as actually experienced by school-age children. Qualitative data were drawn from 32 well children, aged 8 through 11 years, by completion of daily semistructured journals over a period of 6 weeks. Diaries produced 764 stress buffer responses. All data were subjected to content analysis. Sixteen categories among four general themes of intrapsychic comfort, physical-social activities, social support, and physical comfort emerged, beginning a taxonomy of stress buffers as perceived by children. Interesting differences between boys and girls were identified, with implications for research and community nursing practice.

Adaptation, Psychological↗
PubMed1990

Children's coping responses.

Clinical and research data indicate that while nurses attempt to promote health and positive stress outcomes, little is known about actual stress appraisal and coping efforts directly from the child's perspective. This exploration attempted to identify and describe coping responses among well children. Qualitative data were drawn from 32 well children aged 8 through 11 years by interview responses to a sentence completion list and by completion of daily semistructured journals over a period of 6 weeks. All data were subjected to content analysis. Twenty-one categories among four themes of cognitive, cognitive-behavioral, behavioral, and interpersonal coping responses emerged, beginning a taxonomy of children's coping efforts. Results supported some previous studies; however, new categories were identified and implications for research and clinical practice explored.

Adaptation, Psychological↗