Biomedical subjects

A L Olson

Publications and source records attributed to A L Olson.

At least 19 recordsLinked to original sources

PubMed1995

Transcriptional regulation of the human GLUT4 gene promoter in diabetic transgenic mice.

We previously reported that 2400 base pairs (bp) of 5'-flanking DNA is sufficient for tissue-specific and hormonal/metabolic regulation of the human GLUT4 gene in transgenic mice (Liu, M.-L., Olson, A. L., Moye-Rowley, W. S., Buse, J. B., Bell, G. I., and Pessin, J. E. (1992) J. Biol. Chem. 267, 11673-11676). To further define the DNA sequences required for GLUT4 expression, we generated transgenic mice carrying 1975, 1639, 1154, 730, and 412 bp of the GLUT4 5'-flank (hG4) fused to the chloramphenicol acetyltransferase (CAT) reporter gene. The 1975-hG4-CAT, 1639-hG4-CAT, and 1154-hG4-CAT constructs were expressed in a tissue-specific manner identical to the endogenous murine GLUT4 mRNA. Regulation of these reporter gene constructs in insulin-deficient diabetes also paralleled the endogenous gene. In contrast, 730-hG4-CAT was expressed at high levels only in skeletal muscle and at low levels in all of the other tissues examined. Additionally, expression of 412-hG4-CAT was completely unrestricted. Neither the 730-hG4-CAT nor the 412-hG4-CAT reporter genes displayed any insulin-dependent regulation. These data demonstrate that a skeletal muscle-specific DNA element is located within 730 bp of the GLUT4 5'-flanking DNA but that 1154 bp is necessary to direct the full extent of tissue-specific and insulin-dependent regulation of the human GLUT4 gene in transgenic mice.

Adipose Tissue↗

PubMed1995

Characterization of 5'-heterogeneity of the rat GLUT4/muscle-adipose glucose transporter gene product.

To examine the mechanisms responsible for tissue-specific, nutritional, and metabolic regulation of the GLUT4/muscle-adipose specific glucose transporter, we isolated and characterized the properties of the rat GLUT4 gene. Examination of the sequenced 2.5-kilobase flanking DNA revealed substantial identity with that of the mouse and human GLUT4 genes, with the greatest degree of sequence identity within the proximal 1000 basepairs up-stream of the GLUT4 open reading frame. Primer extension analysis identified a unique single transcription initiation site 176 basepairs up-stream from the start of translation. However, ribonuclease mapping revealed the presence of a previously undescribed alternatively spliced form of GLUT4 messenger RNA. Approximately 75% of the GLUT4 transcripts consisted of a fully spliced messenger RNA, and 25% was expressed as an unspliced intron-containing species. The ratios of 5' spliced and unspliced messages were invariant in adipose, cardiac, and skeletal muscle tissues. In vitro translation of reporter constructs containing both the spliced and unspliced leader demonstrated a functional difference between these two transcripts, with the unspliced form translated approximately 5-fold more than the fully spliced species. These data demonstrate the presence of 5'-heterogeneity of the GLUT4 transcripts, which underlies differences in translational efficiency in vitro.

Adipose Tissue↗

PubMed1995

Preventive health care for children.

This article discusses immunization, development, vision, blood pressure, dentition, behavioral, and environmental screening for preschool children. The authors then discuss screening for children in the early school years. Injury and violence prevention and topics of sexuality for the preadolescent are also presented.

Child↗

PubMed1994

Myocyte enhancer factor 2 (MEF2) binding site is essential for C2C12 myotube-specific expression of the rat GLUT4/muscle-adipose facilitative glucose transporter gene.

We have cloned and characterized the rat GLUT4 gene in order to identify the cis-DNA elements responsible for tissue-specific GLUT4 expression. In this study, a variety of luciferase reporter gene constructs were transiently transfected into C2C12 myoblasts and myotubes as a model for skeletal muscle differentiation. These data identified a 103-base pair fragment, located from -522 to -420 relative to the transcription initiation site, that was sufficient to account for GLUT4 C2C12 myotube-specific expression. This fragment was operationally defined as an enhancer since it conferred myotube-specific expression in the context of both the minimal native GLUT4 or the heterologous thymidine kinase promoters in an orientation-independent manner. Further, mutagenesis of this fragment demonstrated that a sequence analogous to the muscle creatine kinase myocyte enhancer factor 2 (MEF2) binding site (-466 and -457) was required for transcriptional activation. Electrophoretic mobility gel shift assays demonstrated specific binding activity to the GLUT4 MEF2 sequences which directly correlated with functional expression. Although this element was capable of directing myotube-specific expression when cloned as multiple copies into luciferase reporter gene constructs, the MEF2 sequence alone was insufficient to enhance GLUT4 expression. These data demonstrated that GLUT4 muscle-specific expression is conferred by a 103-base pair DNA sequence located between -522 and -420 of rat GLUT4 gene. This region encompasses a MEF2 binding site which was necessary, but not sufficient, for transcriptional activation.

Adipose Tissue↗

PubMed1994

In vivo association of Grb2 with pp116, a substrate of the T cell antigen receptor-activated protein tyrosine kinase.

Numerous recent studies have implicated the src homology 2 and 3 domain-containing protein, Grb2, in coupling protein tyrosine kinase signaling pathways with the Ras signaling pathway. Ligation of the T cell antigen receptor results in the activation of both a PTK, and Ras; therefore, we investigated whether Grb2 may serve a similar function in T cells. Here we report that a GST/Grb2 fusion protein associates with several tyrosine phosphoproteins from lysates of T cell antigen receptor-stimulated Jurkat T cells. Two of these proteins, pp36 and pp116, bind to the Grb2 fusion protein with high affinity. Through the use of mutated Grb2 fusion proteins, we demonstrate that pp116 binds the amino-terminal src homology 3 domain of Grb2, the same domain of Grb2 thought to be primarily responsible for its interaction with SOS. We demonstrate further that pp116 associates with Grb2 in vivo, and we provide evidence that in the Jurkat T cell line Grb2 may exist complexed with either pp116 or with SOS.

Adaptor Proteins, Signal Transducing↗

PubMed1994

Regulation of c-fos expression in adipose and muscle tissue of diabetic rats.

Insulin treatment of control rats demonstrated a marked 8-fold transient increase (15 min) in c-fos mRNA in white adipose tissue, which returns to basal levels by 5 h. Similarly, insulin treatment resulted in a rapid 9-fold increase in cardiac muscle c-fos mRNA, which also returned to control values by 1 h. By contrast, insulin treatment resulted in only a small increase in c-jun mRNA levels in both adipose tissue and cardiac muscle. Similarly, the expression of c-jun mRNA was only slightly responsive to insulin in these tissues from streptozocin-induced insulin-deficient diabetic rats. However, insulin treatment of insulin-deficient diabetic rats resulted in a prolonged increase in c-fos message levels in adipose tissue without any significant change in the time course of c-fos mRNA induction/repression in cardiac muscle. These data demonstrate that in contrast to c-jun, c-fos is transiently increased in both cardiac muscle and adipose tissue by insulin treatment. Furthermore, transrepression of the c-fos gene is specifically attenuated in adipose tissue of insulin-deficient diabetic rats, but not in cardiac muscle.

Adipose Tissue↗

PubMed1994

Depressive symptoms and work role satisfaction in mothers of toddlers.

OBJECTIVE: To determine the incidence of depressive symptoms in mothers of toddlers in community pediatric practice. The interaction of employment and work role satisfaction with depressive symptoms was also investigated. SUBJECTS AND METHODS: Depression screening measures were completed by 233 mothers of toddlers (aged 12 to 24 months) at health supervision visits in two community pediatric practices in New Hampshire. Depression was evaluated with a depressive symptom screening inventory modified by Barrett, Oxman, and Gerber from the Hopkins Symptom Checklist for use in primary care population. Data were obtained on parents' socioeconomic variables, hours worked, and whether the mother was satisfied with her current role of being employed or not employed. RESULTS: Depressive symptoms were present in 42% of mothers. Rates of depressive symptoms were similar in employment groups but varied significantly with work role satisfaction. When both employment and satisfaction were considered, mothers who were dissatisfied were 3.7 times more likely to be depressed. After controlling for work role satisfaction, mothers working part time were half as likely to be depressed as mothers working full time and not employed. CONCLUSION: Depressive symptoms are a major problem for mothers of toddlers in middle class pediatric practice. Work role satisfaction and employment status together are related to depressive symptoms.

Adult↗

PubMed1993

Hormonal/metabolic regulation of the human GLUT4/muscle-fat facilitative glucose transporter gene in transgenic mice.

To examine the hormonal/metabolic as well as tissue-specific expression of the GLUT4/muscle-fat facilitative glucose transporter gene, we have generated several transgenic mouse lines expressing a human GLUT4 mini-gene which extends 5.3 kilobases (kb) upstream of transcription start and terminates within exon 10. This construct (hGLUT4-11.5) was expressed in a tissue-specific pattern identical to the endogenous mouse GLUT4 gene. The transcription initiation sites of the transgenic construct were similar to the GLUT4 gene expressed in human tissues. To investigate the hormonal/metabolic-dependent regulation of GLUT4, the transgenic animals were made insulin-deficient by streptozotocin (STZ) treatment. In these animals, STZ-induced diabetes resulted in a parallel decrease in endogenous mouse GLUT4 mRNA and the transgenic human GLUT4 mRNA in white adipose tissue, brown adipose tissue, and cardiac muscle. Similarly, insulin treatment of the STZ-diabetic animals restored both the endogenous mouse and transgenic human GLUT4 mRNA levels. To further define cis-regulatory regions responsible for this hormonal/metabolic regulation, the same analysis was performed on transgenic animals which carry 2.4 kb of the human GLUT4 5'-flanking region fused to a CAT reporter gene (hGLUT4[2.4]-CAT). This reporter construct responded similarly to the human GLUT4 mini-gene demonstrating that the element(s) controlling hormonal/metabolic regulation and tissue specificity all reside exclusively within 2.4 kb of the transcriptional initiation site.

Adipose Tissue↗

PubMed1993

Regulation of the GLUT4/muscle-fat glucose transporter mRNA in adipose tissue of insulin-deficient diabetic rats.

Previous studies have documented that streptozotocin-induced insulin deficiency results in a marked decrease in adipose tissue GLUT4 glucose transporter mRNA levels (Sivitz, W.I., DeSautel, S.L., Kayano, T., Bell, G.I., and Pessin, J.E. (1989) Nature 340, 72-74). In this study, nuclear run-on analysis performed on diabetic and insulin-treated diabetic rats demonstrated that the decrease in GLUT4 mRNA occurs via a diabetes-induced decrease in GLUT4 transcription rate. The decrease in GLUT4 mRNA levels could be prevented by treatment of the diabetic animals with the adenosine receptor agonist phenylisopropyl-adenosine (PIA). Under these conditions, PIA completely blocked the elevation of intracellular cAMP levels associated with insulin deficiency. Surprisingly, isolation of primary rat adipocytes from control animals resulted in a rapid decrease (approximately 20-fold) in GLUT4 mRNA levels by 24 h with a concomitant increase (approximately 70-fold) in GLUT1 mRNA levels. This rapid loss of GLUT4 expression did not correlate with changes in adipocyte cAMP levels and was not prevented by treatment of the cells with either insulin and/or PIA. These data demonstrate that the decrease in GLUT4 transcription induced by insulin deficiency in vivo predominantly results from an increase in intracellular cAMP levels. In contrast, although GLUT4 transcription also decreases in adipocytes when removed from their normal physiological environment, this occurs independent of changes in cAMP levels.

Adipose Tissue↗

PubMed1993

Immunostaining.

Explore the source record for details and available documents.

Humans↗

PubMed1993

Overall function in rural childhood cancer survivors. The role of social competence and emotional health.

This study compared the functioning of 20 rural cancer survivors, aged 6 to 16 years, with that of 40 age- and gender-matched school peers. Social competence and emotional health were evaluated, along with academic performance and physical limitations. Eight measures were used: the teacher and parent Child Behavior Check Lists, the Health Resources Inventory, the Vineland Revised Scale of Social Maturity, the Piers-Harris Child's Self-Concept Scale, the Parcel and Meyers' Health Locus of Control, the Moos' Family Environment Scale, and the Functional Status II(r). Cancer survivors and controls had similar attitudes about self-esteem, family conflicts, physical functioning, social skills, independence, and sense of control over health. Both parents and teachers noted poorer social competence among the cancer survivors than among controls, but parents of survivors reported more behavior problems, whereas teachers stressed poorer school performance. Routine screening for emotional health, social competence, and academic performance should be part of the follow-up care of pediatric cancer survivors.

Activities of Daily Living↗

PubMed1993

Cognitive coping strategies of children with chronic illness.

Children with chronic illness need to adapt to more stresses than do healthy children. Research highlights the problems of children with chronic illnesses but not how they cope in response to the stress created by these problems. Cognitive appraisal of a stressor and of response options is an important aspect of coping. Our cross-sectional study investigated whether children with chronic illness used cognitive strategies for coping as often as did healthy children. One hundred seventy five children from summer camps with juvenile arthritis, asthma, or diabetes were compared with 145 healthy school children. Spontaneous responses to common painful and stressful events were categorized into coping or catastrophizing ideation. Data on anxiety, disease severity, and other sociodemographic variables were obtained. Coping strategies were reported by 64% of children with chronic illness and 63% of healthy children and varied significantly with age (p < .05) in both groups. Children with different chronic illnesses performed similarly except for a trend among children with severe juvenile rheumatoid arthritis who had higher rates of coping. For the individual stressful events, the rate of coping varied from 46% to 86%. The highest rates of coping responses were found with the child's recent personal stressful event where adolescents with chronic illness were twice as likely to offer more complex coping responses. More children with chronic illness than healthy children offered coping strategies in response to venipuncture (p < .001) but not to dental injection. Children with chronic illness report coping as their predominant strategy for adapting to common painful and stressful events.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Psychological↗

PubMed1992

Expression and regulation of the human GLUT4/muscle-fat facilitative glucose transporter gene in transgenic mice.

To study the molecular basis of tissue-specific expression of the GLUT4/muscle-fat facilitative glucose transporter gene, we generated lines of transgenic mice carrying 2.4 kilobases of the 5'-flanking region of the human GLUT4 gene fused to a chloramphenicol acetyltransferase (CAT) reporter gene (hGLUT4[2.4]-CAT). This reporter gene construct was specifically expressed in tissues that normally express GLUT4 mRNA, which include both brown and white adipose tissues as well as cardiac, skeletal, and smooth muscle. In contrast, CAT reporter activity was not detected in brain or liver, two tissues that do not express the GLUT4 gene. In addition, the relative levels of CAT mRNA driven by the human GLUT4 promoter in various tissues of these transgenic animals mirrored those of the endogenous mouse GLUT4 mRNA. Since previous studies have observed alterations in GLUT4 mRNA levels induced by fasting and refeeding (Sivitz, W. I., DeSautel, S. L., Kayano, T., Bell, G. I., and Pessin, J. E. (1989) Nature 340, 72-74), the regulated expression the hGLUT4[2.4]-CAT transgene was also assessed in these animals. Fasting was observed to decrease CAT activity in white adipose tissue which was super-induced upon refeeding. These alterations in CAT expression occurred in parallel to the changes in endogenous mouse GLUT4 mRNA levels. Although CAT expression in skeletal muscle and brown adipose tissue was unaffected, the endogenous mouse GLUT4 mRNA was also refractory to the effects of fasting/refeeding in these tissues. These data demonstrate that 2.4 kilobases of the 5'-flanking region of the human GLUT4 gene contain all the necessary sequence elements to confer tissue-specific expression and at least some of the sequence elements controlling the hormonal/metabolic regulation of this gene.

Adipose Tissue↗

PubMed1992

Intracellular processing of the N-terminal ORF 1a proteins of the coronavirus MHV-A59 requires multiple proteolytic events.

Several polypeptide products of MHV-A59 ORF 1a were characterized in MHV-A59 infected DBT cells, using antisera directed against fusion proteins encoded in the first 6.5 kb of ORF1a. These included the previously identified N-terminal ORF 1a product, p28, as well as 290-, 240-, and 50-kDa polypeptides. P28 was always detected as a discrete band without larger precursors, suggesting rapid cleavage of p28 immediately after its synthesis. Once p28 was cleaved there was little degradation of the protein over a 2-hr period. The intracellular cleavage of p28 was not inhibited by the protease inhibitor leupeptin, in contrast to results obtained during in vitro translation of genome RNA (Denison and Perlman, 1986). These data suggest that different protease activities may be responsible for the cleavage of p28 in vitro and in vivo. The 290-kDa protein was an intermediate cleavage product derived from a precursor of greater than 400 kDa. The 290-kDa product was subsequently cleaved into secondary products of 50 and 240 kDa. The intracellular cleavage of the 290-kDa polypeptide was inhibited by leupeptin at concentrations which did not inhibit the early cleavage of p28 or the cleavage of the 290-kDa product from its larger polyprotein precursor. In the presence of zinc chloride, a product of greater than 320 kDa was detected, which appears to incorporate p28 at its amino terminus. This suggests that at least two protease activities may be necessary for processing of ORF1a proteins, one of which cleaves p28 and is sensitive to zinc chloride but resistant to leupeptin, and the other which cleaves the 290-kDa precursor and is sensitive to both inhibitors. Both the 290- and 240-kDa proteins should contain sequences predicted to encode two papain-like protease activities.

Leupeptins↗

PubMed1992

Human GLUT4/muscle-fat glucose-transporter gene. Characterization and genetic variation.

Four overlapping DNA fragments spanning 32 kb containing the human GLUT4 facilitative glucose-transporter gene were isolated and characterized. The sequence of the GLUT4 gene (approximately 6.3 kb) and 2.0 kb of the promoter region was determined. The sequence of the promoter revealed potential binding sites for transcription factors known to regulate gene expression in muscle cells and adipocytes. However, transfection of constructs including 2 kb of the GLUT4 promoter fused to the bacterial CAT gene into 3T3-L1 adipocytes displayed only weak promoter activity. Because insulin resistance plays a prominent role in the development of NIDDM, genetic variation in the sequence of GLUT4 also was evaluated. Oligonucleotide primer pairs were selected that allowed the protein-coding region of the human GLUT4 gene to be amplified by PCR. The sequence of the protein-coding region of the GLUT4 gene and all intron-exon junctions was determined for a single diabetic Pima Indian and was identical to that of the cloned gene and cDNA. SSCP analysis was used to screen patients with diabetes mellitus and normal, healthy nondiabetic individuals for mutations at the GLUT4 locus. In addition to the silent substitution in the codon for Asn130 (AAC or AAT) and a Val383 (GTC)-->Ile(ATC) replacement described previously, two new variants were identified. One was a T-->A substitution in intron 1 that was found in 1 of 36 NIDDM patients who were typed for this variant. The second was a Ile385(ATT)-->Thr(ACT) replacement that occurred in 1 normal individual and was not found in any of 676 other normal and diabetic subjects. A large and racially diverse group of normal and diabetic individuals also was screened for the Ile383 polymorphism. It occurred in both diabetic and nondiabetic subjects. There is no indication from our data that these polymorphisms are associated with NIDDM.

3T3 Cells↗

PubMed1991

Negative regulation of angiotensinogen gene expression by glucocorticoids in fetal sheep liver.

The effect of glucocorticoids in regulating liver angiotensinogen gene expression was studied in chronically instrumented fetal sheep during the last trimester of gestation and was compared with the expression of other hepatic genes (prothrombin, factor IX, and albumin). Four sets of twins were studied at 118 d of gestation, and three sets were studied at 138 d of gestation (term, 145 d). One of each set of twins was infused intraperitoneally with cortisol (5 mumol.mL-1.h-1) for 48 h, whereas the other twin received the same volume (1 mL/h) of normal saline. Plasma cortisol concentration increased from 0.32 +/- 0.12 and 2.7 +/- 0.12 nmol/100 mL to 44.2 +/- 20.0 and 37.7 +/- 8.2 nmol/100 mL in 118- and 138-d fetuses, respectively, during the cortisol infusion; no changes were observed in fetuses infused with saline alone. At the end of the infusion period, the animals were anesthetized, the fetal liver was removed, and total cellular RNA was isolated and probed for angiotensinogen, prothrombin, factor IX, and albumin. The results demonstrated that cortisol infusion decreased angiotensinogen mRNA by 61% in 138-d fetuses and albumin mRNA expression by 2.4-fold in 118-d fetuses and by 3.4-fold in 138-d fetuses. On the other hand, cortisol had no effect on fetal factor IX gene expression but increased prothrombin mRNA levels by 65% in 118-d fetuses and 62% in 138-d fetuses. Taken together, our results suggest that, during fetal life, angiotensinogen gene expression is negatively regulated by glucocorticoids. This effect is not universal because cortisol increases fetal prothrombin gene expression.

Angiotensinogen↗

PubMed1990

Identification of the spinal cord as a major site of persistence during chronic infection with a murine coronavirus.

After intranasal inoculation, mouse hepatitis virus (MHV) gains entry into the central nervous system (CNS) via the olfactory and trigeminal nerves. Under the appropriate conditions, some mice develop clinically apparent demyelinating encephalomyelitis several weeks later, with virus always present in the spinal cord. To determine the pathway by which virus reaches the cord, brains and spinal cords of infected, asymptomatic mice were analyzed by in situ hybridization. Viral RNA was always detected in the anterior part of the upper spinal cord. A similar analysis of mice with the recent onset of hindlimb weakness showed that viral RNA was detected in the same location. The results suggest that MHV is transported to the spinal cord via well-defined neuroanatomic pathways and that viral amplification with resultant clinical disease occurs from this site of persistence in the anterior spinal cord. This process of viral amplification may involve the generation of viral variants as has been described for MHV-infected rats. No major changes in viral RNA or protein could be detected when MHV isolated from mice with hindlimb paralysis was analyzed. The data suggest that the generation of viral variants is not important in the pathogenesis of the late onset of neurological disease induced by MHV in mice.

Animals↗

PubMed1990

Developmental regulation of angiotensinogen gene expression in sheep.

It has been suggested that the liver is not the main source of angiotensinogen during fetal life in rats, but that the kidney is an important site of fetal angiotensinogen synthesis. In an effort to determine if this phenomenon is specific to the rat or applicable to other species, we compared the ontogenic changes in hepatic and renal angiotensinogen mRNA expression in fetal (60, 90, 118, and 138 d of gestation, term being 145 d), newborn (7 d postnatal), and adult sheep. Total RNA was extracted, subjected to Northern blotting and hybridized using a full-length rat radiolabeled antisense RNA. Angiotensinogen mRNA sequences were detected in all fetal liver samples and appeared to increase 3-fold from 60 to 138 d gestation and then to decrease after birth. In contrast, angiotensinogen mRNA could not be detected in renal cortical tissue of 118 or 138 d fetuses, or newborn or adult sheep. We conclude that, unlike in the rat, liver angiotensinogen gene expression is detectable during the 2nd trimester of gestation in sheep and is developmentally regulated. Furthermore, in contrast to the fetal rat, angiotensinogen mRNA sequences were undetectable in fetal sheep kidney.

Angiotensinogen↗