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Biomedical subjects

K Johnson

Publications and source records attributed to K Johnson.

At least 361 records · Page 20Linked to original sources
PubMed1991

Localization of idiopathic generalized epilepsy on chromosome 6p in families of juvenile myoclonic epilepsy patients.

Juvenile myoclonic epilepsy (JME) is a distinct subform of idiopathic generalized epilepsy of adolescence. Linkage studies with Bf and serologic HLA markers in families of JME patients have shown a tight linkage on chromosome 6. We present a linkage analysis with HLA-DQ restriction fragment length polymorphisms on more extended families, paying particular attention to the epilepsy type of the affected family members. We studied 21 families of JME patients with a total of 143 family members and obtained a highest logarithm of the odds (lod) score of 3.9 (theta m = 0.01, theta f = 0.01) assuming a dominant mode of inheritance and 70% penetrance when family members with JME, absence epilepsy, or epilepsy with generalized tonic-clonic seizures (GTCS) were considered as affected. When we also classified clinically normal family members with generalized spike-wave discharges in the EEG as "affected," the maximum lod score was 4.1 (theta m = 0.01, theta f = 0.3) under a dominant mode of inheritance and 90% penetrance. These findings support the conclusion that a gene locus for a group of idiopathic generalized epilepsies (JME, epilepsy with absences, and epilepsy with GTCS) maps to chromosome 6p.

Chromosomes, Human, Pair 6↗
PubMed1991

Information acquisition and behavioral change: a social marketing application.

Previous literature provides insight into the importance of beliefs and other intrapersonal variables for health-related information acquisition and behavioral change. The results of an empirical investigation evidence the unique strength of the role of core health beliefs for each of the multi-level measures. Directions for the development of effective marketing strategy are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1991

AIDS prevention and college students: male and female responses to "fear-provoking" messages.

This study was designed to examine the effects of fear appeals in AIDS prevention messages and to determine whether or not males and females differ in their response to these appeals. MANOVA results from a sample of 179 junior and senior business students at a mid-Atlantic urban university indicate that significant differences in message effects were associated with type of appeal, gender of the respondent, and the interaction between appeal and gender.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Urinary incontinence: nursing home staff reaction toward residents.

1. ISQ-SR is a reliable and valid tool to measure psychological stress associated with working with urinary incontinent patients. 2. ISQ-SR can be used to measure efficacy of continuing education programs aimed at reducing staff stress associated with urinary incontinence. 3. Eighty percent of the staff reported that they looked for ways to help patients with their incontinence all the time, but only 50% said that they felt comfortable working with urinary incontinent patients all of the time. 4. Sixty-three percent of the staff reported that they felt frustrated about working with urinary incontinence some of the time, indicating a need for continuing education.

Aged↗
PubMed1991

Central auditory processing disorder: a case study.

We carried out extensive audiologic, electrophysiologic, and neuropsychologic testing on a young woman who complained that she had difficulty hearing in her educational environment. Conventional audiometric results, including pure-tone, speech, and immittance audiometry, were all within normal limits. The subject performed normally on tests involving the processing of rapidly changing temporal information, interaural time and intensity difference detection, and both absolute and relative sound localization. Early, middle, late and task-related auditory evoked potentials were essentially normal, although some asymmetry was observed in the middle latency (MLR) and late (LVR) responses. There was, however, a consistent left-ear deficit on dichotic sentence identification, on threshold and suprathreshold speech measures in the left sound field when various types of competition were delivered in the right sound field, and on cued-target identification in the left sound field in the presence of multitalker babble. Results suggest a central auditory processing disorder characterized by an asymmetric problem in the processing of binaural, noncoherent signals in auditory space. When auditory space was structured such that the target was directed to the left ear, and the competition to the right ear, unwanted background was less successfully suppressed than when the physical arrangement was reversed.

Acoustic Impedance Tests↗
PubMed1991

D19S51 is closely linked with and maps distal to the myotonic dystrophy locus on 19q.

Recent genetic linkage studies have mapped the myotonic dystrophy (DM) locus to 19q13.3. All closely linked DM markers identified to date have been located on the centromeric side of the disease locus, with a relatively large genetic interval (9 cM) observed between the nearest distal marker and DM. We show here that the recently described marker p134C is tightly linked to DM (peak lod score 35.8 at peak recombination fraction .006) and confirm the previous suggestion that the p134C locus, D19S51 maps distal to the disease locus. D19S51 and the closest proximal flanking loci, ERCC1 and D19S115 (pE0.8), define a small genetic interval of less than 2 cM that contains the DM locus.

Chromosome Mapping↗
PubMed1990

Lymphocyte adhesion to cultured Peyer's patch high endothelial venule cells is mediated by organ-specific homing receptors and can be regulated by cytokines.

Adhesion of lymphocytes to high endothelial venule (HEV) cells is the first step in the migration of these cells from blood into lymph nodes and Peyer's patches (PP). In the present study, we isolated and cultured HEV cells from PP of the rat and assessed their capacity to interact with lymphocytes. Flow cytometric analysis with a rat HEV-specific mAb KJ-4 revealed that greater than 90% of the cultured cells were stained by the antibody. Furthermore, confluent monolayers of PP HEV cells retained the capacity to support the adhesion of lymphocytes from spleen, thoracic duct, and lymph nodes but not binding of immature cells from thymus and bone marrow, which are deficient in cells capable of binding to HEV in vivo. In addition, intraepithelial lymphocytes that preferentially migrated into mucosal lymphoid tissues were also enriched in cells that adhered to the endothelial monolayers. The binding process required energy, was calcium-dependent, and could be inhibited by cytochalasin D, trypsin, and mixed glycosidase. Interestingly, pretreatment of PP HEV cells with rTNF, IFN-gamma, or granulocyte-macrophage CSF significantly increased the endothelial adhesiveness for thoracic duct lymphocytes in a time- and dose-dependent manner. In contrast, stimulation of lymphocytes with phorbol ester or TNF resulted in the rapid modulation of the surface expression of the PP homing receptor and decrease in lymphocyte binding to normal or TNF-stimulated HEV cells. The adhesion of lymphocytes to normal or cytokine-stimulated HEV cells can be blocked by pretreatment of lymphocytes, but not HEV cells, with the PP homing receptor-specific 1B.2.6 antibody. Taken together, these experiments provide strong evidence that the interaction between lymphocytes and cultured HEV cells are mediated by adhesive mechanisms that regulate lymphocyte entry into PP in vivo and that cytokines can promote HEV adhesiveness for lymphocytes through increased expression of organ-specific ligands on HEV cells.

Animals↗
PubMed1990

Localization of the malignant hyperthermia susceptibility locus to human chromosome 19q12-13.2.

Malignant hyperthermia (MH) is an inherited human skeletal muscle disorder and is one of the main causes of death due to anaesthesia. The reported incidence of MH varies from 1 in 12,000 in children to 1 in 40,000 in adults. MH is triggered in susceptible people by all commonly used inhalational anaesthetics; it is characterized by a profoundly accelerated muscle metabolism, contractures, hyperthermia and tachycardia. Susceptibility to MH (MHS) is predicted by contracture tests on muscle tissue obtained by biopsy. An almost identical disorder known as porcine MH exists in pigs. The genetics of the porcine syndrome have been extensively studied; the locus controlling expression of porcine MH is genetically linked to the glucose phosphate isomerase locus (GPI). In man, GPI has been mapped to the q12-13.2 region of chromosome 19 (refs 10-12). We have now investigated genetic linkage in several extended Irish pedigrees in which MHS is segregating as an autosomal dominant trait. Here we show linkage between MHS and DNA markers from the GPI region of human chromosome 19 with a maximum log likelihood ratio (lod score) of 5.65 at the CYP2A locus. These results indicate that human and porcine MH are most probably due to mutations in homologous genes, and also provide a potentially accurate and noninvasive method of diagnosis for MHS.

Animals↗
PubMed1990

The secD locus of E.coli codes for two membrane proteins required for protein export.

Cold-sensitive mutations in the secD locus of Escherichia coli result in severe defects in protein export at the non-permissive temperature of 23 degrees C. DNA sequence of a cloned fragment that includes the secD locus reveals open reading frames for seven polypeptide chains. Both deletions and TnphoA insertions in this clone have been used in maxicell and complementation studies to define the secD locus and its products. The secD mutations fall into two complementation groups, defining genes we have named secD and secF. These two genes comprise an operon, the first case of two genes involved in the export process being co-transcribed. The DNA sequence of the two genes along with alkaline phosphatase fusion analysis indicates that they code for integral proteins of the cytoplasmic membrane. We suggest that these two proteins may form a complex in the membrane which acts at late steps in the export process.

Amino Acid Sequence↗
PubMed1990

Linkage disequilibrium detected between dystrophia myotonica and APOC2 locus in the Finnish population.

Three polymorphic loci APOC2, CKMM and p134C were used to haplotype 15 Finnish dystrophia myotonica (DM) families representing about one third of all DM patients in this isolated population. Compound APOC2 and CKMM haplotypes reveal linkage disequilibrium: 90% of DM chromosomes co-occur with the haplotypes that occur in 31% of normal chromosomes only. The same disequilibrium is present when only polymorphisms occurring at the APOC2 locus are used. Surprisingly, no statistically significant linkage disequilibrium was discovered at the CKMM locus alone. Of the meiotic events, 84% were informative when both APO2 and CKMM loci were used. When studied selectively, 60% of meiotic events were informative at the APOC2 locus, whereas CKMM alone resulted in 65% meiotic informativeness. The distal marker p134C was found to have an unfortunately low information content in our population.

Alleles↗
PubMed1990

Wrist fracture, heel bone density and thoracic kyphosis: a case control study.

The heel bone density measured by Broadband Ultrasound Attenuation (BUA), the thoracic kyphosis measured by a Kyphometer, height, and weight were compared between 294 women over 49 years of age who sustained a wrist fracture and 294 age-matched women who had not previous wrist, hip or spine fracture. The BUA was significantly less in the women who had wrist fracture (p less than 0.0005), though there was a considerable overlap between the two populations. The women with wrist fracture had significantly greater thoracic kyphosis (p less than 0.0005) and smaller stature (p less than 0.0005). There was no significant difference in weight. There was a significant tendency (p less than 0.0005) for women in the fracture patient group to have both poor BUA and greater kyphosis.

Aged↗
PubMed1990

Genetic evidence that the gene controlling Aub is located on chromosome 19.

DNA from a series of families segregating for Aub was analyzed with a genomic DNA probe which defines a Bg1 I polymorphism for apolipoprotein C II (APOC2). The investigation revealed that the gene for Aub is closely linked to APOC2 (z = 8.43 at theta = 0.00) for paternal and maternal meioses combined, to LW (z = 3.61 at theta = 0.00) in paternal meioses and less closely linked to SE (z = 3.10 at theta = 0.09) for combined paternal and maternal meioses. Therefore, we propose a chromosome 19 location for the Aub gene.

Blood Group Antigens↗