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Biomedical subjects

K Swanson

Publications and source records attributed to K Swanson.

At least 19 recordsLinked to original sources
PubMed2001

Aging and lineup performance at long retention intervals: effects of metamemory and context reinstatement.

Young (18-30 years) and older (62-79 years) adults (N = 96) engaged in a 20-min live interaction with the future target in a lineup task. One month later, participants were interviewed about the events in the prior encounter (with or without context reinstatement), and then they saw a target-present (TP) or target-absent (TA) lineup. The lineup was followed by the Benton Face Recognition Test (A. Benton, A. Sivan, K. Hamsher, N. Varney, & O. Spreen, 1994), which correlated positively with accuracy in TP, especially for young adults. False identification in TA was associated with (a) higher scores on a memory self-efficacy scale and (b) higher recall of information about the initial event, although only for seniors. Results suggested that age-related increases in false identification generalize to ecologically valid conditions and that seniors' performance on lineups is negatively related to verbal recall as well as to self-reports of satisfactory experiences with memory in life.

Adolescent↗
PubMed2001

Lissencephaly with cerebellar hypoplasia (LCH): a heterogeneous group of cortical malformations.

Detailed classification of brain malformations such as lissencephaly has led to the positional cloning of genes required for normal neuronal migration and the identification of unique molecular pathways governing brain structure. While classical magnetic resonance imaging (MRI) patterns of lissencephaly involve primarily the cerebral cortex, malformations in this spectrum can be associated with significant cerebellar underdevelopment and have recently been referred to as lissencephaly with cerebellar hypoplasia (LCH). The phenotypic features of 34 children were found to define 6 subtypes of LCH. Two of these (LCHa and LCHb) were associated with mutation in the LIS1, DCX and RELN genes, respectively. Gene mutations that exemplify four additional classes (LCHc, d, e and f) remained to be determined. Phenotypic features included small head circumference, cortical malformation ranging from agyria to simplification of the gyral pattern and from near normal cortical thickness to marked thickening of the cortical gray matter. Cerebellar manifestations ranged from midline hypoplasia to diffuse volume reduction and disturbed foliation. We conclude that LCH is within the spectrum of DCX and LIS1 mutations, that LCH associated with RELN mutation is distinguished by the severity of cerebellar and hippocampal involvement, and that several distinctive patterns indicate additional genetic mutations that can produce LCH.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2000

Intrusive caregiving and quality of attachment in prenatally drug-exposed toddlers and their primary caregivers.

The relation between caregiver intrusiveness and the quality of attachment was tested among 51 prenatally drug-exposed toddlers and their primary caregivers. Biological mothers and kinship/foster caregivers neither differed as to caregiver intrusiveness nor as to their toddlers' attachment security and attachment organization. Insecure and disorganized/disoriented attachments were found to be more prevalent in this sample than in normal samples. In keeping with recent findings in non-drug-abusing samples (Isabella & Belsky, 1991; Lyons-Ruth, Repacholi, McLeod, & Silva, 1991), more caregivers of toddlers with avoidant or disorganized/disoriented attachments were found to be intrusive than caregivers of toddlers with secure or resistant attachments.

Adult↗
PubMed1996

A gene map of the human genome.

The human genome is thought to harbor 50,000 to 100,000 genes, of which about half have been sampled to date in the form of expressed sequence tags. An international consortium was organized to develop and map gene-based sequence tagged site markers on a set of two radiation hybrid panels and a yeast artificial chromosome library. More than 16,000 human genes have been mapped relative to a framework map that contains about 1000 polymorphic genetic markers. The gene map unifies the existing genetic and physical maps with the nucleotide and protein sequence databases in a fashion that should speed the discovery of genes underlying inherited human disease. The integrated resource is available through a site on the World Wide Web at http://www.ncbi.nlm.nih.gov/SCIENCE96/.

Amino Acid Sequence↗
PubMed1994

Activation of a novel serine/threonine kinase that phosphorylates c-Fos upon stimulation of T and B lymphocytes via antigen and cytokine receptors.

Ligation of Ag receptors in T and B lymphocytes initiates signal transduction cascades which alter the expression of genes that regulate cellular proliferation and differentiation. The transmission of signals from the membrane to the nucleus is mediated principally through the action of protein tyrosine and serine/threonine kinases. We have identified and characterized a novel serine/threonine kinase that phosphorylated the proto-oncogene product, c-Fos, and is termed Fos kinase. Fos kinase was rapidly activated after ligation of the CD3 and CD2 receptors in Jurkat and normal human T lymphocytes and in response to IL-6 and anti-IgM in the human B cell lines AF10 and Ramos, respectively. The phorbol ester, PMA, was also a potent inducer of Fos kinase activity in all of the above populations, suggesting that PKC plays a role in the regulation of this enzyme. Fos kinase phosphorylates c-Fos at a site near the C-terminus, as well as a peptide derived from this region (residues 359-370, RKGSSSNEPSSD), and Fos peptide competitively inhibited c-Fos phosphorylation. Fos kinase was shown to be distinct from other identified serine/threonine kinases, including protein kinase A, protein kinase C, casein kinase II, MAP kinases, p70S6K and p90RSK. Fos kinase was purified by anion exchange chromatography and exhibited an apparent M(r) = 65,000 and isoelectric point = 6.1. Fos kinase may play a role in transcriptional regulation through its capacity to phosphorylate c-Fos at a site required for expression of the transcriptional transrepressive activity of this molecule. Moreover, its rapid activation suggests it may have a wider role within signal transduction cascades in lymphocytes.

Amino Acid Sequence↗
PubMed1992

Conservative treatment of mild/moderate cervical dyskaryosis: long-term outcome.

There is some controversy about the management of women with mild or moderate dyskaryotic cervical smears. To assess the strategy of an established cervical cytology screening programme (Grampian region, northeast Scotland) we identified 500 women who had had mild or moderate cervical dyskaryosis in 1978 or 1979, and 500, matched by age, who had had a normal smear at that time. Follow-up smear results and any subsequent investigation by colposcopy, cone biopsy, or hysterectomy, with biopsy result were recorded. Of the 500 women who initially had an abnormal smear, 300 (60%) had a smear that was normal or inflammatory at their last visit (after seven years' median follow-up). 184 (37%) had undergone biopsy, 97 (19%) of whom were cervical intraepithelial neoplasia grade III or worse. Survival curves for time to biopsy and ten-year biopsy rates show that women with an abnormal smear before their baseline year were the most likely to have a subsequent biopsy. Older women had a biopsy less often and at biopsy were more likely to have minor abnormalities. Mild or moderate dyskaryotic smears should not be an indication for immediate referral for colposcopy, since under a conservative management policy most women return to normal without needing treatment. Nevertheless, the increased risk associated with abnormal smears justifies rigorous surveillance.

Biopsy↗
PubMed1991

Gene sequences suggest inactivation of alpha-1,3-galactosyltransferase in catarrhines after the divergence of apes from monkeys.

The glycosylation enzyme alpha-1,3-galactosyltransferase (alpha 1,3GT; UDPgalactose:beta-D-galactosyl-1,4-N-acetyl-D-glucosaminide alpha-1,3-galactosyltransferase, EC 2.4.1.151) displays a unique pattern of distribution in mammals. It synthesizes an abundance of Gal(alpha 1-3)Gal(beta 1-4)GlcNAc-R (alpha-galactosyl) epitopes within the Golgi apparatus of cells of nonprimate mammals, prosimians, and New World monkeys (platyrrhines). The catarrhines, which include Old World monkeys, apes, and humans, lack this enzyme activity because of the inactivation of the alpha 1,3GT gene. In contrast, the catarrhines produce large amounts of antibodies, designated anti-Gal, against the alpha-galactosyl epitope. The inactivation of the alpha 1,3GT gene in ancestral catarrhines was probably the result of an intensive evolutionary pressure for alteration in the makeup of cell surface carbohydrates (i.e., suppression of alpha-galactosyl epitope expression) and for the production of the anti-Gal antibody. To determine the period in which the alpha 1,3GT gene was inactivated in ancestral catarrhines, comparative sequencing of a 370-base-pair region of this gene was performed by polymerase chain reactions with DNA of various primates. The data suggest that alpha 1,3GT inactivation occurred rather late in the course of catarrhine evolution (less than 28 million years ago), as separate events in apes and in Old World monkeys, after the two groups diverged from each other.

Animals↗
PubMed1990

Prenatal diagnosis of alpha-thalassemia by polymerase chain reaction and dual restriction enzyme analysis.

Asian couples at risk for a fetus with homozygous alpha-thalassemia (hydrops fetalis) are often identified by their low erythrocyte mean corpuscular volume (MCV) and normal hemoglobin electrophoresis when little time remains to test their genotypes by restriction enzyme analysis. DNA analysis is performed directly on chorionic villi or amniocytes remaining after an aliquot is used to establish a backup cell culture. The polymerase chain reaction (PCR) protocol quickly determines whether the fetus has hydrops fetalis without waiting for cultured cells to grow. Previously, growing cultured fetal cells to obtain more fetal material to establish unambiguously the fetal genotype with two independent restriction enzyme digests absorbed a significant portion of the time remaining to complete prenatal diagnosis. A dual restriction enzyme digestion protocol was development using a 3' zeta-globin probe to clearly distinguish the most common alpha-thalassemia deletions that represent nearly all the alpha-thalassemia haplotypes in Southeast Asia.

Base Sequence↗
PubMed1987

Ethylnitrosourea treatment increases lectin binding to mouse germ cells.

Germ cell toxicity was assessed by investigating the binding of FITC-labeled lectins to mouse testis cells before and 18 days after treatment with ethylnitrosourea (ENU). Flow cytometry of testis cells dual-labeled with FITC-lectin plus the DNA stain, propidium iodide, allowed analysis of haploid (1C), diploid (2C), and dividing (4C) cell populations. Soybean agglutinin, wheat germ agglutinin, concanavalin A and Limax flavus agglutinin bound to normal mouse testis cells containing 1C, 2C or 4C DNA. Asparagus pea lectin and Bandeireae simplicifolia I isolectin B4 did not. ENU treatment reduced the number of testis cells and increased lectin binding, particularly of those lectins which bound to untreated cells.

Animals↗
PubMed1987

Effect of trypsinization on lectin binding to germ cells from ICR and T/t6 mice.

Flow cytometry was used to quantify the binding of fluorescein isothiocyanate (FITC)-labeled lectins to testis cells from ICR and T/t6 mice before and after trypsin treatment. Soybean agglutinin, wheat germ agglutinin, and concanavalin A bound well to testis cells of both mouse strains. Limax flavus agglutinin (LFA) bound very slightly and Ulex europeas agglutinin (UEA) did not bind at all. Trypsinization increased binding of soybean agglutinin and decreased binding of wheat germ agglutinin in both mouse strains, providing evidence for masked carbohydrate-binding sites on the surface of germ cells. It did not affect binding of the other lectins. Trypsin treatment was an attempt to increase lectin binding, particularly the binding of LFA and UEA to the reported T/t-specific carbohydrates, sialic acid, and L-fucose, respectively. These studies indicate that the T/t6 locus alleles do not alter the surface carbohydrate content of testis cells sufficiently to be detected by lectin-binding differences.

Animals↗
PubMed1986

Reaction of Lewy bodies with antibodies to phosphorylated and non-phosphorylated neurofilaments.

The reaction of Lewy bodies in the substantia nigra and the sympathetic ganglia was studied in 10 cases of Parkinson's disease and other Lewy body-related conditions, using monoclonal antibodies to non-phosphorylated (02-40) and phosphorylated (03-44 and 07-5) neurofilaments. Although many Lewy bodies were unstained, a peripheral ring of positive immunoreactivity was frequently observed. This reaction was more common and more intense with antibodies to phosphorylated neurofilaments, suggesting a posttranslational phosphorylation of elements in the Lewy body. Although Lewy bodies appear to have some antigenic sites in common with neurofilaments, certain differences between neurofilaments and Lewy body filaments are emphasized.

Antibodies, Monoclonal↗
PubMed1985

Immunologic and clinical correlates of bronchial challenge responses to Bermuda grass pollen extracts.

We have studied 26 patients with asthma who had positive skin tests for Bermuda grass pollen antigen (BGP) with history, immunologic assays, and bronchial challenge with BGP. In these patients IgE anti-BGP RAST titers were higher in those with positive, 6.8 +/- 4.4% (mean +/- SEM) compared to those with negative bronchial challenges, 2.7 +/- 0.4% (p less than 0.02). Historical data did not predict bronchial challenge response. IgG4 anti-BGP RAST was not different in patients with positive and negative challenges but was markedly increased, 15.3 +/- 11.9%, in patients who had previously had BGP immunotherapy when compared to untreated patients, 3.6 +/- 5.1% (p less than 0.01). IgE anti-Bermuda grass appears to be the major contributor to susceptibility to BGP bronchial challenge. IgG4 anti-Bermuda grass is apparently unrelated to the sensitivity to challenge but appears to be a significant component of the immunologic response to immunotherapy.

Antibodies, Anti-Idiotypic↗