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Biomedical subjects

N Ernst

Publications and source records attributed to N Ernst.

At least 19 recordsLinked to original sources
PubMed2001

Extraction of long-chain fatty acids in isolated rat heart during acute low-flow ischemia.

UNLABELLED: Although beta-oxidation of fatty acids is suppressed rapidly during ischemia, the behavior of fatty acid extraction at different flow rates is incompletely understood. This study assessed the relationship between flow and extraction of (123)I-iodophenylpentadecanoic acid (IPPA) in the isolated heart model, especially at low flow. METHODS: Isolated hearts from male Wistar rats (n = 15) were subjected to retrograde perfusion with constant flow (Krebs Henseleit solution containing 10 mmol/L glucose). A latex balloon in the left ventricle allowed isovolumetric contractions and ventricular pressure measurements. The extraction of (123)I-IPPA was assessed with the indicator dilution technique and (99m)Tc-albumin as the intravascular reference. The flow was either increased from the control flow (8 mL/min) until 300% or reduced until 10%. (123)I-IPPA extraction was measured three times before and 10 min after flow alteration. The tracer uptake was estimated from the product of net extraction and flow. RESULTS: The mean (123)I-IPPA extraction at the control flow (third measurement) was 51.6% +/- 2.8%. Between flow rates of approximately 25% and 300%, (123)I-IPPA extraction increased exponentially at decreasing flow rates. At flow rates < or =25% of the control flow, (123)I-IPPA extraction was exponentially higher than predicted. (123)I-IPPA uptake and flow changed largely in parallel. During low flow, the rate-pressure product showed the expected decline (perfusion-contraction matching). CONCLUSION: The extraction of (123)I-IPPA is preserved and slightly increased (relative to flow) during acute low-flow ischemia.

Animals↗
PubMed2000

Photon emission spectroscopy of individual oxide-supported silver clusters in a scanning tunneling microscope

Photon emission spectra of individual alumina-supported silver clusters have been measured for the first time. The light emission stimulated by electron injection from the tip of a scanning tunneling microscope can be assigned to the (1,0) mode of the Mie-plasmon resonance in small silver particles. As cluster sizes decrease, the resonance position shifts to higher energies and the linewidth increases. In the size range examined (1.5-12 nm), intrinsic size effects are discussed as possible origins for the observed size dependence of the Mie resonance.

Journal Article↗
PubMed1997

Heterotypic cell-cell adhesion of human mast cells to fibroblasts.

Skin mast cells are typically located in the perivascular or perineural connective tissue. We observed that HMC-1 mast cells growing in suspension adhered efficiently to (> 90% of cells) and spread on top of fibroblast monolayers and to a lesser degree on purified extracellular matrix proteins. Since adhesive interactions determine cell migration and tissue localization we studied the mechanism. It was found that HMC-1 cells attach to collagen I and fibronectin, laminin, collagen IV and vitronectin, but not to collagens III and VI or hyaluronic acid. Adhesion to fibronectin, collagen I and laminin was completely inhibited by mAbs blocking beta 1-integrins, whereas adhesion of HMC-1 cells to vitronectin was inhibited by anti-alpha v-chain mAbs. However, attachment of HMC-1 cells to fibroblasts was not influenced by mAbs blocking beta 1- or alpha v-chain function, by RGD peptides or by mAbs interfering with other receptors, most notably c-kit. Identical results were obtained with normal mast cells isolated from human foreskin. These results indicate that human mast cells attach to fibroblasts independently of beta 1- or alpha v-integrins as well as of c-kit receptor-mediated mechanisms. The functional characteristics observed (i.e. only partial sensitivity to trypsin and EDTA, no increase in trypsin sensitivity by pretreatment with EDTA) suggest that cadherin receptors were not involved, and it is likely that the adhesion process observed involved not-yet-defined heterotypic cell-cell adhesion receptors.

Antibodies, Monoclonal↗
PubMed1996

Interleukin-10 production in malignant melanoma: preferential detection of IL-10-secreting tumor cells in metastatic lesions.

IL-10 mRNA expression and protein production in established melanoma cell lines and freshly cultured primary and metastatic melanoma cells was examined. The in situ distribution of IL-10 in native melanoma tissue was also investigated by immunohistochemistry in primary tumors, metastases, benign melanocytic nevi and normal skin of healthy persons and melanoma patients. IL-10 mRNA, but not IL-10 protein in the culture supernatant, was found in 1 of 4 cultured melanoma cells of primary tumors, while 3 of 6 melanoma-metastasis-derived cultures expressed both IL-10 mRNA and protein. No IL-10 was detected in skin biopsies of healthy volunteers or in the healthy skin of melanoma patients; nor was IL-10 found in congenital melanocytic nevi. In only 1 of the 11 examined primary malignant melanomas was IL-10 immunoreactivity detected within the cytoplasm of cells in the tumor. On the other hand, 4 of 9 metastases clearly displayed scattered IL-1O+ cells. In all sections with IL-10-positive cells, the cells were positive for HMB-45. No co-expression of CD3 and IL-10 was observed. The data suggest that melanoma cells themselves are the main origin of IL-10 in tumor specimens in vivo. The preferential expression of IL-10 in metastatic lesions and in cultured cells from metastases might indicate an increased spreading potential of IL-10-secreting melanoma-cell clones.

Base Sequence↗
PubMed1995

T cell receptor repertoire in polymyositis: clonal expansion of autoaggressive CD8+ T cells.

In polymyositis (PM), CD8+ T cell receptor (TCR) alpha/beta + cells invade and destroy major histocompatibility complex class I-positive muscle fibers. We combined polymerase chain reaction (PCR) and double-fluorescence immunocytochemistry to analyze the T cell receptor (TCR) repertoire expressed in muscle of PM patients. In patient 1, inverse PCR revealed a preferential usage of TCR V alpha 33.1, V beta 13.1, and V beta 5.1. Six of six TCR V alpha 33.1+ clones and five of seven V beta 13.1+ clones had identical nucleotide sequences. In contrast, the V beta 5.1+ TCRs were more heterogeneous. Similar results were obtained with an independent PCR method using primers specific for TCR V alpha 33, V beta 13, or V beta 5. No TCR sequences could be amplified from noninflammatory control muscle. Furthermore, none of the TCR sequences found in PM muscle could be detected in blood from the same patient or from a normal control subject. Immunohistochemistry confirmed that V beta 5.1 and V beta 13.1 were overrepresented in the muscle lesions of this patient. 32% of all CD8+ T cells were V beta 13.1+, and 16% were V beta 5.1+. However, approximately 60% of the CD8+ T cells that invaded muscle fibers were V beta 13.1+, whereas 10% were V beta 5.1+. In patient 2, 50% of the T cells were V beta 5.1+, and as in patient 1, these T cells were mainly located in interstitial areas. In patient 3, > 75% of the autoinvasive T cells stained with an anti-V beta 3 mAb. Sequence analysis of 15 PCR clones amplified with a V beta 3-specific primer showed that 9 (60%) sequences were identical. The results suggest that (a) a strikingly limited TCR repertoire is expressed in PM muscle; (b) there is a dissociation between the TCR usage of autoinvasive and interstitial T cells; and (c) the autoinvasive T cells are clonally expanded.

Amino Acid Sequence↗
PubMed1985

Defining scholarly activity in nursing education.

In an attempt to address the question of what activities should be considered scholarly, thereby warranting their inclusion in a nursing faculty evaluation model, a study was undertaken which surveyed all National League for Nursing accredited baccalaureate educational programs. The items in the instrument were generated utilizing the Delphi method and a pilot study established inter-respondent reliability. A response rate of 73% was attained. Scholarly activity was considered highly important in evaluation for promotion and tenure in over 50% of the schools. There were distinct differences in the activities deemed scholarly when respondents were broken down into categories such as size and type of institution and the existence or non-existence of graduate nursing programs in the same institution.

Colorado↗
PubMed1983

Selected nutrient intakes of free-living white children ages 6-19 years. The Lipid Research Clinics Program Prevalence Study.

We report energy intake and selected nutrient intakes-protein, fat (total, saturated, and polyunsaturated), carbohydrate (total, starch, and sucrose), and cholesterol-for 1251 white children ages 6-19 years. The data were obtained, by means of a 24-h dietary recall, from children who were randomly selected from the North American populations studied by the Lipid Research Clinics Program. Females (N = 584) consumed about 2000 kcal daily, an intake that remained relatively constant throughout the age groups studied. Males (N = 667) had an energy intake of 2000 kcal/day during childhood that increased to over 3000 kcal/day in adolescence. Energy sources for both sexes were approximately 15% protein, 38% total fat, 15% saturated fat, 6% polyunsaturated fat, 48% total carbohydrate, 19% starch, and 11% sucrose; cholesterol intake averaged about 145 mg/1000 kcal. For both sexes, fat intake increased with age. Compared to females, males ingested greater amounts of cholesterol and total and saturated fat.

Adolescent↗
PubMed1981

Alcohol and high-density lipoprotein cholesterol.

Associations between alcohol intake and levels of high-density lipoprotein (HDL) cholesterol were examined in 2473 men and 1530 women seen as part of the random sample at visit 2 of the Lipid Research Clinics Prevalence Study. More men than women reported alcohol intake. The alcoholic beverage preference differed by age and sex. The levels of HDL cholesterol were higher in drinkers than in nondrinkers. The statistically significant associations varied somewhat by age; however, the average correlation coefficient was 0.21 for men and 0.25 for women. HDL cholesterol levels were lower in those who reported never drinking alcohol than in occasional drinkers.

Adult↗
PubMed1980

Changes in plasma lipids and lipoproteins after a modified fat diet.

20 male and female patients with type II hyperlipoproteinaemia and 10 normal male and female subjects were fed for 11--15 days a eucaloric diet containing less than 300 mg cholesterol with a polyunsaturated to saturated fatty-acid ratio of about 2.0. Male subjects and patients and female patients showed statistically significant decreases in plasma total cholesterol and low-density lipoprotein (LDL) cholesterol levels; the change in LDL-cholesterol was not significant in female subjects. The changes in lipid and lipoprotein levels in patients were greater than those in subjects, (except for the changes in high-density lipoprotein (HDL) in women, which were similar), which suggested that the magnitude of change depended on initial levels. This difference was not present when the data were evaluated as percent change. Mean levels of HDL-cholesterol decreased in both patients and subjects. However, the proportion of total cholesterol contributed by HDL and LDL, and hence the HDL/LDL ratio, was unchanged from pre-diet levels.

Adult↗
PubMed1980

The NHLBI nutrition data system.

A standardized system for the collection and processing of dietary information in large-scale studies is described. Components of the system include interviewer and coder training, certification and continuing education, automated procedures for identifying and quantitating fat, guides for classifying and quantitating foods, system maintenance and quality control procedures, and a food table containing about 800 food items and 450 recipe items. The system is flexible enough to respond to market changes in formulation. Unique automated features make the system particularly useful in identifying and quantitating different dietary fats. These features could be modified to meet nutritional demands of other studies.

Cholesterol, Dietary↗
PubMed1980

The association of plasma high-density lipoprotein cholesterol with dietary intake and alcohol consumption. The Lipid Research Clinics Prevalence Study.

We examined the associations of diet and alcohol consumption with levels of high-density lipoprotein (HDL) cholesterol using cross-sectional data from 4855 white participants, ages 20 years and older, seen at visit 2 of the Lipid Research Clinics Prevalence Study. There was a strong positive gradient of HDL cholesterol levels with reported amount of alcohol intake in both men and women, regardless of type of alcoholic beverage consumed. We found a difference in HDL cholesterol levels between the two groups of participants who reported no alcohol consumption during the past week. Those who said that they never drank had lower mean HDL cholesterol levels than those who reported that they did drink but had not consumed any alcohol during the past week. Weaker inverse relations (p < 0.05) were found between HDL cholesterol levels and intakes of total carbohydrate sucrose and starch (percent calories and grams). Dietary saturated, monounsaturated and polyunsaturated fat intakes were unrelated to HDL cholesterol levels; similarly, no association was seen for HDL cholesterol and total calories and total fat. Cholesterol intake (mg and mg/1000 calories) was generally unrelated to HDL cholesterol levels, except in women not taking exogenous gonadal hormones.

Adult↗