PubMed Health⌕ Search

Biomedical subjects

R Larson

Publications and source records attributed to R Larson.

At least 55 records · Page 3Linked to original sources
PubMed1991

Daily companionship in late childhood and early adolescence: changing developmental contexts.

The study employs time-sampling data to examine age differences in the quantity and quality of children's and young adolescents' daily experience with their families, friends, and alone. Participants (ages 9-15) carried electronic pagers for 1 week and reported their companionship, location, and affect at random times when signaled by the pagers. Findings show a dramatic decline in amount of time spent with family, with older students reporting half as much time with their families as younger students. Among boys, this family time was replaced by time spent alone; among girls, by time alone and with friends. Affect reported when with family became less positive between the fifth and seventh grade, but was more positive again in the ninth grade for boys. Affect with friends became more favorable across this age period; affect when alone did not vary. These age differences suggest changes in adolescents' daily opportunities for cognitive growth, emotional development, and social support.

Adolescent↗
PubMed1990

The cognitive moderation of daily stress in early adolescence.

Utilized daily diary data to investigate age differences in the moderation of stressful daily events. Data from 243 fifth- to ninth-grade boys and girls, collected over a period of 1 week, were used to examine the moderation effect that expectation and past experience have upon affective response to daily stressors and uplifts. Responses indicate that across a variety of contexts expected daily events are less upsetting than unexpected events for both children and young adolescents. However, among the older students in the sample expectation of chronic negative events appears to exacerbate, rather than alleviate, their upsetting quality. These findings are discussed in terms of the increase in stress associated with early adolescence and the possibility that the chronic stress experienced during this period diminishes the utility of anticipatory coping.

Adaptation, Psychological↗
PubMed1990

Weight and eating concerns among pre- and young adolescent boys and girls.

The emergence of weight and eating concerns in pre- and young adolescents and the relations of these concerns to daily experience and psychologic adjustment were investigated. Four hundred eighty-one children from fifth to ninth grades completed a Weight and Eating Concerns Scale, a depression inventory, self-esteem and body image scales, and reported their daily experiences by the Experience Sampling Method. Girls tended to report more weight and eating concerns than boys. This discrepancy increased with age. In older girls (eighth and ninth graders) extreme weight and eating concerns were associated with other signs of emotional maladjustment. Girls who experience emotional distress may try to compensate for the strain by controlling body shape and in doing so, may place themselves at risk for developing an eating disorder. Boys currently appear to be protected from this difficulty. Our findings suggest that excessive weight and eating concerns in young adolescent girls signal psychologic maladjustment which may require attention.

Adolescent↗
PubMed1990

MDR1 transcript levels as an indication of resistant disease in acute myelogenous leukaemia.

The expression of the MDR1 gene was studied by Northern blot analysis in leukaemic cell specimens obtained from 74 patients with acute myelogenous leukaemia (AML). No relationship was found between MDR1 RNA levels and FAB type of leukaemia or patient age. Transcript levels tended to be highest in the leukaemic cells of patients with a history of toxic exposure or preleukaemia compared with 'standard risk' patients at diagnosis but the differences were not significant (P = 0.07). Patients whose leukaemic cells contained high MDR1 transcript levels were difficult to induce into remission and, if remission was induced, the remissions were short. Hence high levels of MDR1 expression may explain, at least in part, the ineffectiveness of anthracycline antibiotic containing treatment regimens in some patients with AML.

Adolescent↗
PubMed1989

The encoded primary sequence of a rice seed ADP-glucose pyrophosphorylase subunit and its homology to the bacterial enzyme.

Rice seed ADP-glucose pyrophosphorylase cDNA clones were isolated by screening a lambda expression library prepared from rice endosperm poly(A+) RNA with a heterologous antibody raised against the spinach leaf enzyme and subsequently by nucleic acid hybridization. One cDNA plasmid, possessing about 1650 nucleotides, was shown by both DNA and RNA sequence analysis to contain the complete ADP-glucose pyrophosphorylase coding sequence of 483 amino acids. The primary sequence displayed a putative leader peptide presumably required for transport of this nuclear encoded protein into the amyloplasts, a differentiated starch containing plastid. The leader peptide, however, showed little sequence homology with transit peptides displayed by other known nuclear encoded proteins localized in the chloroplasts. A comparison of the primary sequence of the putative mature subunit to the Escherichia coli pyrophosphorylase showed two regions displaying significant homology. These two conserved regions contain residues shown previously to be essential for the allosteric regulation and catalytic activity of the E. coli enzyme. Differences in the primary sequences of the plant and bacterial enzyme may reflect the distinct nature of the allosteric effectors that control these enzymes.

Amino Acid Sequence↗
PubMed1989

Structure and expression of the rice glutelin multigene family.

A near full-length cDNA and three genomic clones for rice (Oryza sativa L.) glutelin were isolated and studied. Based on nucleic acid sequence and Southern blot analyses, the three isolated glutelin genomic clones were representative members of three gene subfamilies each containing five to eight copies. A comparison of DNA sequences displayed by relevant regions of these genomic clones showed that two subfamilies, represented by clones Gt1 and Gt2, were closely related and evolved by more recent gene duplication events. The 5'-flanking and coding sequences of Gt1 and Gt2 displayed at least 87% homology. In contrast, Gt3 showed little or no homology in the 5'-flanking sequences upstream of the putative CAAT boxes and exhibited significant divergence in all other portions of the gene. Conserved sequences in the 5'-flanking regions of these genes were identified and discussed in light of their potential regulatory role. The derived primary sequences of all three glutelin genomic clones showed significant homology to the legume 11 S storage proteins indicating a common gene origin. A comparison of the derived glutelin primary sequences showed that mutations were clustered in three peptide regions. One peptide region corresponded to the highly mutable hypervariable region of legume 11 S storage proteins, a potential target area for protein modification. Expression studies indicated that glutelin mRNA transcripts are differentially accumulated during endosperm development. Promoters of Gt2 and Gt3 were functional as they direct transient expression of chloramphenicol acetyltransferase in cultured plant cells.

Amino Acid Sequence↗
PubMed1989

Daily emotional states as reported by children and adolescents.

Hour-to-hour emotional states reported by children, ages 9-15, were examined in order to evaluate the hypothesis that the onset of adolescence is associated with increased emotional variability. These youths carried electronic pagers for 1 week and filled out reports on their emotional states in response to signals received at random times. To evaluate possible age-related response sets, a subset of children was asked to use the same scales to rate the emotions shown in drawings of 6 faces. The expected relation between daily emotional variability and age was not found among the boys and was small among the girls. There was, however, a linear relation between age and average mood states, with the older participants reporting more dysphoric average states, especially more mildly negative states. An absence of age difference in the ratings of the faces indicated that this relation could not be attributed to age differences in response set. Thus, these findings provide little support for the hypothesis that the onset of adolescence is associated with increased emotionality but indicate significant alterations in everyday experience associated with this age period.

Adolescent↗
PubMed1989

Long-term outcomes for elderly survivors of prolonged ventilator assistance.

Care of ventilator-dependent patients requires considerable resources, yet the long-term outcomes of this type of care have rarely been described. We retrospectively investigated the posthospital course of elderly patients who survived an episode of prolonged ventilator dependency to describe survival rates, subsequent use of health care resources, and functional abilities. Our data suggest that the use of prolonged mechanical ventilation in the elderly produces few survivors at considerable expense. Poor overall outcomes occurred despite considerable consumption of medical and nursing resources by the survivors.

Aged↗
PubMed1989

Is feeling "in control" related to happiness in daily life?

This research concerns the relation of subjective control and happiness within normal daily experience. Respondents from several nonclinical samples rated their feelings of control at randomly-selected moments during a week in their lives, following the procedures of the Experience Sampling Method. Analyses consider the relation of these ratings to similar ratings of affective states, first, within persons and, second, between persons. The within-person analyses show relatively little moment-to-moment correlation of subjective control and affective states. For many persons there is no correlation at all and on the average people report feeling only slightly more happy at times when feeling in control. The between-persons analyses yield findings that are more in line with explanations of subject control, showing that individuals reporting higher average daily control also experience greater average happiness. The results confirm that a generalized sense of control is important to well being in daily life, but for nondisturbed individuals short-term experiences of discontrol are not accompanied by substantial distress.

Adolescent↗
PubMed1989

Cloning of the cDNA and sequence of the human proliferating-cell nucleolar protein P120.

The 120 kDa proliferating-cell nucleolar antigen described by Freeman et al. (Cancer Res. 48:1244; 1988) is the most cancer specific of the proliferation-associated nucleolar proteins identified thus far. It is localized in a novel nucleolar microfibrillar structure recently described by Ochs et al. (Cancer Res. 48:6523; 1988). The amino acid sequence has been determined by a combination of cDNA and genomic DNA sequences. This molecule contains, consecutively, four major domains: a basic domain, an acidic domain, a hydrophobic and methionine-rich domain, and a domain rich in cysteine and proline residues. The isolated cDNA was shown to code for the HeLa P120 protein as shown by a similarity in immunoreactivity, mobility on sodium dodecylsulfate-polyacrylamide gel electrophoresis, and patterns of partial digestion of the Escherichia coli-expressed P120 and the HeLa nucleolar P120 protein. This protein is of special interest because it is expressed in early G1 and, in studies to date, it has not been detected in benign tumors and most normal resting tissues.

Amino Acid Sequence↗
PubMed1989

Protooncogene expression and the clinical characteristics of acute nonlymphocytic leukemia: A Leukemia Intergroup pilot study.

Northern blot analysis was used to assess the level of expression of five protooncogenes and histone H3 in the bone marrow cells of patients with acute nonlymphocytic leukemia (ANLL). The relationship between the level of gene expression and the clinical characteristics of the disease and response to therapy was studied. The levels of expression of c-myc and c-myb are weakly correlated and are unrelated to French-American-British (FAB) type of ANLL. The levels of expression of c-fms, c-fes, and c-fos are highly correlated with each other and are highest in leukemia with a monocytic component (c-fms v FAB = .71, c-fes v FAB = .75). High levels of c-myc expression are associated with a high probability of not responding to remission induction therapy (P = .004). The converse is true for c-fms expression levels. High levels of expression of c-myc or c-myb are associated with short remissions (P = .059 and .065, respectively), perhaps because they are associated with a high capacity for leukemic cell self-renewal and/or an inability of leukemic cells to differentiate in response to chemotherapy.

Bone Marrow↗
PubMed1988

Low O6-alkylguanine DNA alkyltransferase activity in the peripheral blood lymphocytes of patients with therapy-related acute nonlymphocytic leukemia.

Chemotherapeutic agents such as procarbazine, which produce methylated bases in DNA, are used to treat many Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) patients. A small proportion of such patients develop secondary malignancy. We examined the possibility that those patients who develop secondary malignancy have low endogenous levels of O6-alkylguanine DNA alkyltransferase (AGT) activity and are therefore more sensitive to the mutagenic and carcinogenic effects of their treatment. We assayed AGT activity in peripheral blood lymphocytes from patients with HD, NHL, acute nonlymphocytic leukemia (ANLL) de novo, and therapy-related ANLL, as well as a group of normal control subjects. Studies in normal controls showed that at least over a short term of 1 week, individuals have characteristic AGT levels, although some individuals sampled repeatedly over several months showed high variation. Mean AGT activities +/- SE for the various groups studied were (fmol/micrograms of DNA): normal control group, 7.05 +/- 0.36; HD and NHL patients (prior to treatment), 4.97 +/- 0.42; HD-NHL patients receiving procarbazine, 3.88 +/- 0.44; ANLL de novo, 7.78 +/- 1.72; and therapy-related ANLL, 4.30 +/- 0.58. AGT activity decreased in the peripheral blood lymphocytes of some individuals taking procarbazine. The mean AGT activity in the procarbazine-treated patients was low, as was the activity for the therapy-related ANLL patients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

Acute leukemia occurring after radiotherapy and chemotherapy with a nitrosourea, PCNU.

Secondary acute leukemias can occur in patients who have been treated with chemotherapy. Several reports have shown that treatment with nitrosoureas can result in secondary leukemia, but this is the first report implicating the investigational drug PCNU as a cause. This case is unique because of the cytogenetic findings, the short latency period between the chemotherapy and the diagnosis of leukemia, and the successful treatment of the leukemia with high-dose cytarabine (ara-C).

Adenocarcinoma↗
PubMed1988

Molecular cloning and nucleotide sequence of the pestivirus bovine viral diarrhea virus.

The RNA genome of the cytopathic NADL isolate of bovine viral diarrhea virus (BVDV) has been molecularly cloned and the nucleotide sequence determined. The cloned sequence was 12,573 nucleotides in length, corresponding to a molecular weight of 4.3 X 10(6), having a base composition of 32.2% A, 25.7% G, 22.1% U, and 20.0% C. However, the sequences at the 5' and 3' termini of the RNA have not been unequivocally established. A single major open reading frame extending the length of the molecule was found in the viral-sense (positive polarity) sequence. This open reading frame was capable of encoding 3988 amino acids, representing 449 kDa of protein.

Amino Acid Sequence↗
PubMed1988

Proteins encoded by bovine viral diarrhea virus: the genomic organization of a pestivirus.

The genome of bovine viral diarrhea virus (BVDV) contains a single large open reading frame capable of encoding 449 kDa of protein. Short segments from along the length of the molecularly cloned BVDV genome were engineered so as to be expressed as bacterial fusion polypeptides in Escherichia coli. These BVDV analog fusion proteins were used as immunogens to generate a panel of sequence-specific antisera. These antiserum reagents were in turn employed in immunoprecipitation analyses to identify the authentic BVDV protein to which they were directed. The results allowed for the identification and positioning along the genome of BVDV gene products accounting for approximately 83% of the coding capacity of the virus. A preliminary map of the genetic organization of BVDV is presented and discussed.

Antibodies, Viral↗