PubMed Health⌕ Search

Biomedical subjects

R Larson

Publications and source records attributed to R Larson.

At least 73 records · Page 4Linked to original sources
PubMed1988

Epstein-Barr virus latent infection membrane protein alters the human B-lymphocyte phenotype: deletion of the amino terminus abolishes activity.

A latent infection membrane protein (LMP) encoded by the Epstein-Barr virus (EBV) genome in latently infected, growth-transformed lymphocytes alters the phenotype of a human EBV-negative B-lymphoma cell line (Louckes) when introduced by gene transfer. These LMP-expressing cells exhibit increased homotypic adhesion due to increased expression of the adhesion molecules LFA-1 and ICAM-1. Increased homotypic adhesion could foster B-cell growth by facilitating autocrine growth factor effects. LFA-3 expression is also induced. The induction of LFA-3 and ICAM-1 results in increased heterotypic adhesion to T lymphocytes. This could result in more effective T-cell immune surveillance. Since LMP is expressed in EBV-transformed lymphocytes and has been demonstrated to transform rodent fibroblasts in vitro, a wide range of possible effects on B-lymphoma cell growth were assayed. In the Louckes B-lymphoma cell line, EBV LMP causes increased cell size, acid production, plasma membrane ruffling, and villous projections. Although cell proliferation rate was not greatly affected, the steady-state intracellular free calcium level, transforming growth factor beta responsiveness, and expression of the lymphocyte activation markers (CD23 and transferrin receptor) were increased. Thus, LMP appears to be a mediator of EBV effects on B-cell transformation. In transfected lymphoma cells, LMP localizes to patches at the cell periphery and associates with the cytoskeleton as it does in EBV-transformed B lymphocytes or in rodent fibroblasts. A partially deleted form of LMP (D1LMP) does not aggregate in patches or associate with the cytoskeleton and had little effect on B-cell growth. Thus, cytoskeletal association may be integral to LMP activity.

Antibodies, Monoclonal↗
PubMed1987

Validity and reliability of the Experience-Sampling Method.

To understand the dynamics of mental health, it is essential to develop measures for the frequency and the patterning of mental processes in every-day-life situations. The Experience-Sampling Method (ESM) is an attempt to provide a valid instrument to describe variations in self-reports of mental processes. It can be used to obtain empirical data on the following types of variables: a) frequency and patterning of daily activity, social interaction, and changes in location; b) frequency, intensity, and patterning of psychological states, i.e., emotional, cognitive, and conative dimensions of experience; c) frequency and patterning of thoughts, including quality and intensity of thought disturbance. The article reviews practical and methodological issues of the ESM and presents evidence for its short- and long-term reliability when used as an instrument for assessing the variables outlined above. It also presents evidence for validity by showing correlation between ESM measures on the one hand and physiological measures, one-time psychological tests, and behavioral indices on the other. A number of studies with normal and clinical populations that have used the ESM are reviewed to demonstrate the range of issues to which the technique can be usefully applied.

Activities of Daily Living↗
PubMed1987

High-dose cytosine arabinoside as the initial treatment of poor-risk patients with acute nonlymphocytic leukemia: a Leukemia Intergroup Study.

Sixty-seven patients with newly diagnosed acute nonlymphocytic leukemia (ANLL) who were considered to be poor candidates for treatment with cytosine arabinoside (ara-C)/anthracycline antibiotic therapy were treated with high-dose ara-C (HDara-C) remission induction therapy. Thirty-four of the 67 patients had a hematologic disorder before developing acute leukemia or had a history of exposure to marrow toxins, 23 patients were greater than 70 years old, and 10 patients had medical problems that were felt to be a contraindication to therapy with an anthracycline antibiotic. Forty-two percent of patients entered complete remission (CR), whereas 22% failed to enter remission because of persistent leukemia. Treatment was associated with substantial toxicity varying from nausea and vomiting to irreversible cerebellar toxicity. Thirty-four percent of patients died during therapy. Poor performance status, a low serum albumin, and a low platelet count were associated with death during remission induction therapy, whereas a high pretherapy leukemic cell mass and a large number of residual leukemic cells in the marrow after six days of therapy were associated with treatment failure due to persistent leukemia.

Acute Disease↗
PubMed1986

High-dose cytosine arabinoside in the treatment of preleukemic disorders: a leukemia intergroup study.

Fifteen patients with myelodysplastic/myeloproliferative disorders were treated with high-dose cytosine arabinoside therapy. While severe toxicity was produced in every patient, only two of the 15 patients entered complete remission and two achieved partial remission status. The therapeutic responses were confined to patients who had severe myelofibrosis of apparently recent onset.

Adult↗
PubMed1986

Limited efficacy of a four-day course of high-dose cytosine arabinoside in the treatment of poor-risk patients with acute nonlymphocytic leukemia.

High-dose cytosine arabinoside therapy was administered to 29 patients with poor-prognosis acute nonlymphocytic leukemia. In an attempt to reduce toxicity, therapy was divided into an initial 4-day course of therapy, followed by a 3-day course of the marrow aspirate examined 1 week after the end of treatment contained substantial numbers of leukemic cells. Of the 29 patients, 5 entered complete remission, 2 of them after the initial 4-day course of therapy. The toxicity of split-course therapy was the same as that of conventional 6-day high-dose cytosine arabinoside therapy. This study demonstrates that the modification of high-dose cytosine arabinoside therapy used in this study failed to reduce toxicity and produced a lower remission rate than that obtained with the 6-day course of therapy.

Acute Disease↗
PubMed1986

Gene-dependent flavonoid 3'-hydroxylation in maize.

The influence of the gene Pr on flavonoid 3'-hydroxylase activity in maize is described. Specific activities are presented for the hydroxylase in seedlings and aleurone tissue homozygous dominant and recessive and heterozygous for Pr. Specific activity levels in both tissues increased in a nearly direct proportion with the increase in Pr dosage, which is consistent with Pr being the structural gene for the hydroxylase. Regression analysis of the gene dosage:enzyme activity comparison yielded correlation coefficients of 0.979 and 0.959 for the seedlings and aleurone, respectively. Quantitative identification of the cyanidin and pelargonidin in the aleurone indicated that cyanidin increased with an increase in dominant Pr, while pelargonidin decreased, although the increases and decreases observed were not directly proportional to the gene dosage. Comparison of the cyanidin/pelargonidin ratio to the gene dosage ratio in the different tissues showed a strong correlation (0.998), which demonstrates that the dosage of Pr controls the ratio of cyanidin to pelargonidin. Cyanidin was found at a low concentration in aleurone homozygous for pr. Hydroxylase activity in maturing field plants reaches its peak concentration near anthesis and is present at an appreciable concentration in mature plant tissue homozygous for pr, as well as in seedlings homozygous for pr. Suggestion is made that pr could be a hypomorphic allele or that a duplicate gene for Pr could exist to account for the hydroxylase activity in homozygous pr tissue. Evidence for the hydroxylase in the aleurone and the seedlings and the pigment ratio data from the aleurone suggest that Pr is indeed a structural gene for NADPH:flavonoid 3'-hydroxylase.

Cytochrome P-450 Enzyme System↗
PubMed1986

Daily well-being of older adults with friends and family.

Family members are the major source of physical and emotional support for older adults, yet researchers suggest that friendships have a stronger bearing on subjective well-being. In this research we sought an explanation for this inconsistency in older adults' immediate experiences with friends. Retired adults provided self-reports on their subjective states at random moments during a typical week. Analyses of these reports confirmed the prediction that older adults have more favorable experiences with their friends than with family members. The difference is partly attributable to the greater frequency of active leisure activities with friends, but is also due to unique qualities of interactions with friends that facilitate transcendence of mundane daily realities. We propose that friends provide an immediate situation of openness, reciprocity, and positive feedback that engenders enjoyment and subjectively meaningful exchanges.

Aged↗
PubMed1985

Bulimia: disturbed patterns of solitude.

This research suggests that daily solitude has a central role in bulimia. A sample of 15 bulimic patients and 24 normal controls carried electronic pagers for one week and filled out self-reports on their experience in response to randomly timed signals. The bulimics reported the lowest mood states when alone at home, the context in which their symptomatic behavior usually takes place. Further, those who reported the worst experiences in this context were the one's showing the most severe behavioral and affective manifestations of the disorder.

Adult↗
PubMed1985

Being alone versus being with people: disengagement in the daily experience of older adults.

This research investigates the quantity and quality of time alone or "solitude" in the daily lives of older adults. A sample of 92 retired adults carried electronic pagers for 1 week and filled out self-reports on their companionship and internal states in response to signals received at random times. Analysis of the 3,412 reports indicates that those who were unmarried and living alone spent a majority of their waking hours alone and experienced low affect and arousal when in this dominant part of their lives. For the married, solitude was also a major part of daily life, filling 40% of their time, but, although it was related with somewhat lower affect, it was also related with higher arousal. These results suggest that being alone is not a wholley negative experience for this age group, especially for those who have the regular companionship of a spouse.

Aged↗
PubMed1984

Clinical study of mastitis-metritis-agalactia in sows in Illinois.

Mastitis-metritis-agalactia (MMA) occurred in 6.9% of 16,405 farrowings recorded over 1 year (1981) in 31 Illinois swine herds. Prevalence of MMA among herds ranged from 1.1% to 37.2% and was not correlated to herd size. There was a significant positive correlation between the prevalence of MMA and the housing system wherein sows were moved from pasture gestation to crates immediately before farrowing. A significant seasonal peak of MMA was found for the third quarter of the year (10.3%). Mean prevalence of MMA was 13% in pluriparous sows and 4.2% in primiparous sows. The difference was not significant. Sows with MMA gave birth to more live pigs per litter compared with healthy sows (+0.7 pigs per litter). The number of stillbirths and pigs found dead after birth also was higher in sows with MMA (+4.6%). Total pig mortality until 1 week of age was 56% in litters of pluriparous sows with MMA and 17% in litters of healthy pluriparous sows and, respectively, 41% and 15% in litters of primiparous sows. The mean number of pigs per litter surviving at 1 week of age was 5.6 in pluriparous sows with MMA and 9.3 in healthy sows and, respectively, 6.2 and 8.3 in primiparous sows. For all herds investigated, mean litter size at birth (including stillbirths) was 11.0. Total pigs mortality until 1 week of age was 31%. Pig losses attributable to MMA, at 6.9% prevalence of the disease, were 4% of all pigs born and 12.9% of the pig mortality until 1 week of age.

Age Factors↗
PubMed1984

Influence of B and Pl on UDPG:Flavonoid-3-O-glucosyltransferase in Zea mays L.

The influence of the genetic constitution at the B and Pl loci on UDPG:flavonoid-3-O-glucosyltransferase activity is described. More than a 90% reduction in activity is found when either B or Pl was present in the homozygous recessive condition. A positive correlation between quercetin-3-O-glucoside and pelargonidin-3-O-glucoside production is observed for all genotypes tested. Changes in UFGT activity during plant development are described for R-r B Pl plants.

Anthocyanins↗
PubMed1984

Characterization of bovine viral diarrhea virus proteins.

Virus-specific proteins were examined in cultured cells infected with bovine viral diarrhea virus. By using antisera obtained from virus-infected animals, three major virus-specific polypeptides with molecular weights of 115,000 (115K), 80K, and 55K were observed. Minor proteins of 45,000 and 38,000 daltons were also noted. Tryptic peptide mapping indicated that the 115K and the 80K polypeptides were structurally related. The 55K protein was glycosylated and appeared not to be related to the 115K and 80K proteins. Pulse-chase experiments failed to demonstrate any procursor-product relationship among any of these proteins, and all three polypeptides were found in purified virion preparations. The significance of these findings with respect to the replication of bovine viral diarrhea virus is discussed.

Animals↗
PubMed1984

Cell-free translation of bovine viral diarrhea virus RNA.

Bovine viral diarrhea virus RNA was translated in a reticulocyte cell-free protein synthesizing system. The purified, 8.2-kilobase, virus-specific RNA species was unable to serve an an efficient message unless it was denatured immediately before translation. In this case, several polypeptides, ranging in molecular weight from 50,000 to 150,000 and most of which were immunoprecipitated by bovine viral diarrhea virus-specific antiserum, were synthesized in vitro. When polyribosomes were used to program cell-free synthesis, mature viral 80,000- and 115,000-molecular-weight proteins were detected; no precursor to the viral 55,000-molecular-weight glycoprotein was noted. The implications of these results with respect to virus-specific protein synthesis are discussed.

Animals↗
PubMed1984

Alcohol and marijuana use in adolescents' daily lives: a random sample of experiences.

High school students filled out reports on their experiences at random times during their daily lives, including 48 occasions when they were using alcohol or marijuana. Alcohol use was reported primarily in the context of Friday and Saturday night social gatherings and was associated with a happy and gregarious subjective state. Marijuana use was reported across a wider range of situations and was associated with an average state that differed much less from ordinary experience.

Adolescent↗
PubMed1984

Localized cicatricial pemphigoid (Brunsting-Perry). A transplantation experiment.

Normal skin was transplanted into a cicatricial plaque in a patient affected with localized, benign pemphigoid of the Brunsting-Perry type. Eight weeks later, the transplanted tissue was removed and found to have IgG at the basement membrane zone on immunofluorescence microscopy. Subepidermal bullae developed at the graft-donor site. Local factors and trauma may be important in the pathogenesis of this variant of cicatricial pemphigoid.

Administration, Oral↗
PubMed1983

Apple II computer software for DNA and protein sequence data.

In our attempt to make the aid of a computer for the molecular biology laboratory available on a low-cost basis, we have improved the programs that we published recently. We have experienced in our laboratory, and have learned from others, that the average lab has an increasing demand to use a time-sharing-independent computer for the bulk of data handling. A microcomputer can give this independence. At the same time, a microcomputer can serve as a terminal for the few computer jobs, such as data communication or extensive search programs, which have to be conducted on a time-sharing basis. In this paper, we describe the programs which can be executed on a Apple II microcomputer using the Apple Language System. This system gives the researcher the opportunity to learn to handle sequence data, and it also includes a word processing system useful in writing letters and manuscripts and storing text.

Amino Acid Sequence↗
PubMed1983

Characterization of virus-specific RNA synthesized in bovine cells infected with bovine viral diarrhea virus.

Infection of bovine kidney cells with bovine viral diarrhea virus resulted in the synthesis of a single species of virus-specific RNA. Electrophoresis of this RNA on agarose-urea and agarose-formaldehyde gels indicated that it had a molecular weight of 2.9 X 10(6), corresponding to 8,200 bases (8.2 kilobases). This 8.2-kilobase RNA was resistant to RNase A treatment at 1 microgram/ml but was digested at higher concentrations of RNase (10 micrograms/ml). Sedimentation on neutral sucrose gradients indicated that the majority of this RNA (98%) sedimented at 21S, with a small amount sedimenting at 33S. Sedimentation on formaldehyde-containing sucrose gradients resulted in the conversion of all of the RNA to the faster-sedimenting form. At no time after infection were we able to detect virus-specific RNA species of lower molecular weight than the 8.2-kilobase RNA. The implications of these findings with respect to the means of replication of various togaviruses are discussed.

Animals↗