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Biomedical subjects

L M Olson

Publications and source records attributed to L M Olson.

At least 55 records · Page 3Linked to original sources
PubMed1992

Human plasma lipoproteins regulate apolipoprotein E secretion from a post-Golgi compartment.

The molecular regulation of apolipoprotein E (apoE) synthesis and secretion is incompletely understood. In this study, we have examined the effect of human low density lipoprotein (LDL) on apoE mRNA and protein levels in HepG2 and other eukaryotic cells. Exposing HepG2 cells to LDL for times up to 4 h resulted in an increase in 35S-labeled apoE accumulation in the medium by 2.2-fold, relative to serum free controls (n = 10, p < 0.001), with no changes in apoE mRNA levels. Similar observations have been made in JeG-3 cells and Chinese hamster ovary cells stably transfected with human apoE cDNA constructs. These results indicate that the LDL effect operates at a post-transcriptional level. In pulse-chase experiments, the LDL effect on apoE accumulation in the media was observed when it was added only during the chase even in the presence of cycloheximide, indicating that LDL is functioning at a post-translational level. The use of brefeldin A (BFA), an agent that impedes protein transport from the endoplasmic reticulum to the Golgi apparatus, suggests that the LDL effect occurs in a post-Golgi compartment. The addition of protease inhibitors could not duplicate the effects of LDL on the apoE accumulation in the medium. ApoA-I accumulation in the medium of HepG2 cells, but not albumin, was also significantly increased by 1.9-fold (n = 5, p < 0.001).

Albumins↗
PubMed1991

Apolipoprotein E synthesis by cultured human ovarian granulosa cells: regulation by human chorionic gonadotropin and cholesterol.

OBJECTIVE: Apolipoprotein E (Apo E) is a surface component of several classes of plasma lipoproteins and functions as a receptor ligand for the low-density lipoprotein (LDL) (B/E) receptor, the hepatic E receptor, and the LDL receptor related protein. In continuing studies of Apo E synthesis by extrahepatic steroidogenic tissue, we have examined Apo E production and its control in cultured human granulosa cells (GC). DESIGN: Human GC obtained at the time of oocyte aspiration for in vitro fertilization were cultured, and the following parameters were measured: progesterone secretion into the medium, Apo E synthesis and secretion, and Apo E messenger ribonucleic acid (mRNA) content of the GC. RESULTS: Human chorionic gonadotropin induces a decrease in Apo E protein synthesis and Apo E mRNA content. The addition of aminoglutethimide (which blocks cholesterol conversion to pregnenolone) and/or LDL (which provides the cell with cholesterol), both result in an increase in Apo E protein synthesis and Apo E mRNA content. These latter findings are in agreement with studies in nonsteroidogenic cells, which show that Apo E production is positively correlated with cell cholesterol content.

Aminoglutethimide↗
PubMed1991

Fatal poisoning among American Indian, Hispanic, and non-Hispanic white children in New Mexico, 1958 to 1982.

Childhood fatalities from unintentional poisoning are a substantial health problem in New Mexico, which ranks second in the nation in injury-related mortality rates. To determine the extent of poison-related mortality in children in this state, and to examine time trends and differences in mortality rates in New Mexico's American Indian, Hispanic, and non-Hispanic white children aged 0 to 14 years, we analyzed vital records collected from 1958 to 1982. New Mexican children experienced higher mortality rates than US white children of similar age--approximately eight times higher for children under 5 years old. Of the three ethnic groups, American Indian children had the highest mortality rates from unintentional poisoning during the 25-year period. Children less than 5 years old were at the highest risk for poison-related fatalities among all three ethnic groups.

Adolescent↗
PubMed1990

Injury mortality in American Indian, Hispanic, and non-Hispanic white children in New Mexico, 1958-1982.

Childhood fatalities from injuries are a serious public health problem in New Mexico, a state which ranks second in the nation in injury-related mortality rates. To determine the extent of injury mortality in children in this state, and to examine time trends and differences in mortality rates in New Mexico's American Indian, Hispanic, and non-Hispanic white children aged 0-14 years, we analyzed vital records collected from 1958 to 1982. American Indian children experienced the highest mortality rates from all external causes combined. Among all three major ethnic groups, children aged 0-4 years were at the highest risk for injury fatalities. Unintentional injuries accounted for 85% of all injury-related deaths. Motor vehicle crashes and drowning were the first and second leading causes of death in all three groups, while other important causes of death included fire, choking on food or other objects, poisoning, and homicide. Although the fatality rates on most types of injuries decreased over the 25-year period, childhood fatality rates for motor vehicle crashes and homicide increased in each ethnic group. Despite the overall decrease in injury mortality rates in New Mexican children, the rates are excessively high compared to other states, especially in American Indian children.

Adolescent↗
PubMed1990

Kinetics of cell-mediated cytotoxicity in mice fed diets of various fat contents.

We previously reported lower mitogen-induced blastogenic and cytotoxic activity of splenocytes from C3H/OUJ female mice fed 20% soybean oil (SBO) in their diet compared to those fed 5% SBO. The present study examined the kinetics of cell-mediated cytotoxicity using the same animal model and dietary treatments. Kinetic parameters were determined by analyzing the lytic efficiency of splenocytes cultured for various times with several concentrations of radiolabeled P815 mastocytoma cells. The apparent avidity constant (K1/2) of the reaction was not changed by dietary SBO intake (1.0 +/- 0.2 x 10(5) cells for 20% SBO versus 1.3 +/- 0.3 x 10(5) cells for 5% SBO). However, the maximum velocity (Vmax) of the reaction for splenocytes from mice fed 20% SBO was significantly lower than that for splenocytes from mice fed 5% SBO (1.4 +/- 0.2 x 10(4) cells/h for 20% SBO versus 2.3 +/- 0.4 x 10(4) cells/h for 5% SBO, p less than 0.05). The evidence indicates that the rate of target cell lysis, but not the avidity of the lymphocytes for the target cell antigen, was altered by increasing dietary SBO concentration.

Animals↗
PubMed1988

Effects of ammonium acetate and sodium cholate on N-methyl-N'-nitro-N-nitrosoguanidine-induced colon carcinogenesis of rats.

This study was conducted to determine the effects of ammonium acetate alone or in combination with sodium cholate upon N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced colon carcinogenesis in rats. Ammonia, acetate, and deconjugated bile acids are produced by microbial enzymes in the gastrointestinal lumen. One hundred twenty male Sprague-Dawley rats, weighing 196 +/- 2 g at 8 wk of age, were given four intrarectal doses of MNNG (2 mg/dose) over 2 wk. They were then randomly assigned among four treatment groups, each containing 30 rats. The groups were arranged in a 2 x 2 factorial design and given intrarectal infusions of the agents under study in 0.3 ml of double-distilled water 3 times weekly for 52 wk beginning 4 wk after the initial MNNG treatment. The experimental treatments were: double-distilled water as control; ammonium acetate (24.8 mg of ammonia); sodium cholate (2 mg of cholic acid); and a combination of ammonium acetate and sodium cholate. Ammonium acetate treatment increased the number of rats with fecal blood 4-fold after 56 wk, and this was associated with a higher incidence of adenocarcinomas with a polypoid morphology. The incidence and total number of carcinomas in situ (high grade dysplasia) increased with ammonium acetate treatment. Ammonium acetate increased the total number of adenocarcinomas. Sodium cholate had no significant main effects on the incidence or morphology of colon lesions. The data support the conclusion that ammonium acetate treatment acted as a promoting agent in MNNG-induced colon carcinogenesis.

Acetates↗
PubMed1988

The religious community as a partner in health care.

In-depth structured interviews were conducted with spokespeople for 176 inner-city churches regarding perceptions of existing community problems, number of currently offered church-based social and health programs, and potential interest in church sponsorship of new maternal and child health programs. The sample of respondents represented 78% of the 227 churches located in a low-income, primarily black urban area with 150,000 residents. The typical church participating in the survey was Baptist with a congregation of 100 to 500 people, most of whom were not community residents. The leading community problems identified by the clergy were, in descending order: lack of jobs, teenage pregnancy, gang crime, school drop-outs, and hunger. The perception of community problems matched the church services offered as measured by the number of food and clothing pantries. Few churches had ongoing programs for neighborhood youths. Although many of these same churches expressed interest in expanding services for mothers, adolescents and children, few perceived themselves as having the necessary staff, funds, or technical expertise to conduct such programs.

Black or African American↗
PubMed1988

High mortality with severe dystrophic cardiac calcinosis in C3H/OUJ mice fed high fat purified diets.

Severe degenerative myocardial disease occurred in female C3H/OUJ mice fed purified diets for 36 weeks; the diet contained 5% or 20% fat as non-hydrogenated soybean oil. Deaths of lactating females of this group (17/35 high fat diet and 7/35 low fat diet animals) were due to sudden cardiovascular collapse. Cardiomegaly with marked atrial and ventricular myocardial mineralization was seen at necropsy. Histologically, the random, myopathic foci were characterized by severe myocardial degeneration, mineralization, and fibrosis. Mural thrombosis, pulmonary arteriosclerosis, and mild myocardial inflammatory cell infiltrates were also present. Pathological changes were similar to those of dystrophic cardiac calcinosis, an incidental necropsy finding in certain mouse strains.

Animals↗
PubMed1987

Identical twins with malrotation and type IV jejunal atresia.

Identical twins are reported, who associated with maternal anaphylactic shock at 101/2 weeks gestation, acquired a type IV jejunal atresia with total absorption of the small bowel beyond the third portion of the duodenum and persistence of the most terminal length of ileum in the ileocolic artery in an apple peel configuration. Both infants survived a tapered jejunoileostomy and have undergone a successful transition to a regular diet. This accidental occurrence in two infants at the same time and in an identical fashion is a rare event.

Diseases in Twins↗
PubMed1987

Lymphocyte activation, cell-mediated cytotoxicity and their relationship to dietary fat-enhanced mammary tumorigenesis in C3H/OUJ mice.

The effects of dietary soybean oil (SBO) concentration (5 vs. 20% by weight) on mammary tumorigenesis, mitogen-induced blastogenesis, cell-mediated cytotoxicity and serum and lymphocyte fatty acid composition were studied in C3H/OUJ female mice. Weanling mice fed 20% SBO for 9 mo had a higher incidence (89 vs. 65%) and greater average size (2.9 vs. 1.9 g) of mammary tumor virus type S breast tumors than mice fed 5% SBO. The response of isolated splenocytes to the T-cell mitogens concanavalin A and phytohemagglutinin was 20-25% lower in mice fed 20% SBO than in mice fed 5% SBO for 20 wk. There was no effect of SBO concentration on the splenocyte response to lipopolysaccharide E55:B5, a B-cell mitogen, or to pokeweed mitogen, and B- and T-cell mitogen. Cell-mediated cytotoxicity to allogenic P815 tumor cells was 20% lower in mice fed 20% SBO than in mice fed 5% SBO for 12 wk. The lower cell-mediated immunity associated with 20% SBO was not due to changes in the fatty acid composition of the two major splenocyte membrane phospholipids, phosphatidylcholine and phosphatidylethanolamine. However, serum levels of linoleic acid were higher in mice fed 20% SBO. Raising dietary SBO from 5 to 20% by weight was associated with increased mammary tumorigenesis, reduced T-cell blastogenesis and lower cell-mediated cytotoxicity.

Animals↗
PubMed1985

The role of C5 in septic lung injury.

One proposed mechanism for the pathogenesis of lung injury in septic animals is the stimulation by C5a of granulocytes to produce and release toxic oxygen radicals that damage cellular membranes in pulmonary capillaries. The authors have investigated the possible role of C5 in septic lung injury, utilizing C5-sufficient and C5-deficient twin mice strains. In this lethal sepsis model, mean survival time is increased in C5-deficient mice in comparison to the survival of their C5-sufficient twins. Morphometric results demonstrate a significant increase in intracapillary granulocrit and air-blood barrier thickness 24 hours after cecal ligation and puncture in C5-sufficient septic mice. Similarly, mean arterial pO2 is significantly decreased in the C5-sufficient animals. Intracapillary granulocrit, air-blood barrier thickness, and arterial pO2 are normal in the septic C5-deficient twins of these animals. These data support the hypothesis that C5 is involved in the pathogenesis of septic lung injury.

Animals↗
PubMed1985

The circadian pacemaker in the Aplysia eye sends axons throughout the central nervous system.

Each eye of Aplysia contains a population of electrically coupled pacemaker neurons whose synchronous activity can be recorded from the optic nerve as a compound action potential (CAP). The CAP frequency continues to show a circadian rhythm even when the eye is isolated from the animal and maintained in constant conditions, and thus it contains an autonomous circadian pacemaker, which may reside in the pacemaker neurons. The pacemaker neurons, along with retinal photoreceptors, send axons out of the optic nerve, which connects to the cerebral ganglion of the central nervous system (CNS). Pacemaker neurons, but not photoreceptors, may contain an aminergic transmitter, possibly dopamine (DA). We describe the central projections of optic nerve fibers using horseradish peroxidase filling of the cut optic nerve, and transport of radiolabeled macromolecules after selective exposure of the eye to [3H] leucine, which labels both pacemaker neurons and photoreceptors. We were able to determine the projections of pacemaker axons by exposing the eye to [3H]-3,4-dihydroxyphenylalanine [( 3H] DOPA and [3H]DA, which is preferentially taken up and transported by the pacemaker neurons. Pacemaker axons project bilaterally to the cerebral, pedal, and pleural ganglia and may extend as far as the abdominal ganglion. We corroborate this anatomical evidence by recording an orthodromic CAP in the optic nerve that had originated in the eye and subsequently recording the CAP in the CNS connectives and nerves that contained [3H]DOPA-labeled fibers. These results suggest that circadian pacemaker information from the eye is widely distributed throughout the CNS, including neural structures known from studies by others to mediate circadian-regulated behaviors, such as locomotion. Thus, Aplysia can now be used as a model system to examine the influence of the central projections of an identified circadian pacemaker on behavior, such as locomotion, at the level of identified central neurons.

Afferent Pathways↗
PubMed1984

A clinical model for enhancing adolescent ego identity.

A model of identity formation based on the cognitive developmental stages of social perspective-taking is described. The model assumes that identity can be achieved through cognitive strategies of considering the self in relation to one friend, one's family, the peer group, and society. Two studies were undertaken to test the model. In Study 1, 28 college students participated in a two week program in which the experimental students were asked to take the perspective of each social entity above and then to consider how the self was like and unlike these. The experimentals gained more than the controls on the identity subscale of Rasmussen's EIS. Fifty-nine college students participated in Study 2 which used a more sensitive discrepancy score measure on a revised identity scale. Discrepancy scores in an analysis of covariance indicated that the experimentals were higher than the controls at post-test and at a one month follow-up.

Adolescent↗