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Biomedical subjects

M A Jensen

Publications and source records attributed to M A Jensen.

12 recordsLinked to original sources
PubMed1992

Contrasting effects of alpha, beta, and gamma interferons on nonspecific suppressor function in multiple sclerosis.

Interferons are biological molecules with antiviral, antiproliferative, and immunomodulatory actions. Interferon alpha (IFN-alpha) and -beta are potentially useful in the treatment of multiple sclerosis (MS). IFN-gamma, in contrast, increases the frequency of exacerbations of MS. In this study, we compared the effect of recombinant human IFN-alpha, -beta, and -gamma on suppressor function in patients with MS. Nonspecific suppressor cell function, measured in a concanavalin A suppressor assay, was significantly decreased in 16 patients with progressive MS (mean percent suppression +/- SEM, 14.4 +/- 5.5 in patients with MS, 33.5 +/- 4.8 in 16 normal subjects; p less than 0.001). Recombinant human IFN-beta augmented suppressor function in MS to 45.4 +/- 5.1% (p less than 0.001) and in control subjects to 56.8 +/- 3.8% (p less than 0.001). Similarly, recombinant human IFN-alpha improved suppression in MS to 43.0 +/- 5.6% (p less than 0.001) and in control subjects to 51.1 +/- 5.9% (p less than 0.001). In contrast, recombinant human IFN-gamma had no effect on suppressor function in patients with MS and in control subjects. This study shows that IFN-alpha and -beta augment deficient suppressor function in MS, whereas IFN-gamma has no effect on suppressor function in the progressive phase of the disease.

Adult↗
PubMed1992

Preferential increase of IL-2R+ CD4+ T cells and CD45RB- CD4+ T cells in the central nervous system in experimental allergic encephalomyelitis.

We examined lymphocytes isolated from the spinal cord (SC), peripheral blood (PB) and lymph nodes (LN) draining the immunization site of Lewis rats with acute experimental allergic encephalomyelitis (EAE). Cells were analysed for T cell subset markers CD4 (mAb W3/25) and CD8 (mAb OX8), for IL-2R (mAb OX39), and for high molecular mass leukocyte common antigen (LCA, CD45RB) expression (mAb OX22). T cells expressing high (CD45RB+) or low (CD45RB-) molecular mass LCA are of different maturational stages and/or separate lineages. CD4+ T cells were more predominant in SC than in PB and LN; CD8+ T cells were scarce in SC but common in PB and LN. Activated CD4+ T cells (IL-2R+) were common in the SC and LN but infrequent in blood. CD4+ T cells that were CD45RB+ were scarce in the SC. In contrast, the majority of CD4+ T cells in the PB and LN were CD45RB+. The preferential accumulation of IL-2R+ CD4+ T cells and of CD45RB- CD4+ T cells in the central nervous system (CNS) indicates that a selective mechanism directs cell egress into CNS lesions in EAE.

Animals↗
PubMed1991

Improvements in the chain-termination method of DNA sequencing through the use of 7-deaza-2'-deoxyadenosine.

Significant improvements in the quality of DNA sequencing data have been shown when deoxyadenosine triphosphate (dATP) is replaced by 7-deaza-2'-deoxyadenosine triphosphate (c7dATP). The use of c7dATP in conjunction with 7-deaza-2'-deoxyguanosine triphosphate (c7dGTP) further decreases anomalies in electrophoretic mobility which are caused by compressions involving G and/or A residues. This effect is observed for both isotope-based and fluorescence-based sequencing approaches. Replacing dATP with c7dATP also results in a higher degree of uniformity in the frequency of chain termination reactions, when such terminations involve the incorporation of fluorescence-labeled dideoxynucleotides by T7 polymerase. These improvements in the gel-resolution and distribution of chain-terminated DNA products result in higher accuracy in both manual and automated base assignment.

Adenosine Triphosphate↗
PubMed1990

Interferon beta augments suppressor cell function in multiple sclerosis.

Suppressor cell function has been previously reported to be decreased in patients with progressive multiple sclerosis (MS). The abnormality could not be corrected in vitro and was present even after patients were treated with immunosuppressive agents. We now report that interferon beta augments suppressor cell function in vitro in progressive MS. Nonspecific suppressor cell function as measured in a concanavalin A (Con A) suppressor assay was reduced in 24 MS patients (mean percent suppression, 19.6 +/- 2.2) when compared to 19 normal subjects (mean percent suppression, 35.0 +/- 3.3). The data are highly significant (p less than 0.001). When recombinant human interferon beta (10(3) units/ml) was added to lymphocyte cultures with Con A, suppressor activity improved significantly. The mean percent suppression improved from 19.6 +/- 2.2 to 37.8 +/- 2.6 in MS (p less than 0.001) and from 35.0 +/- 3.3 to 46.2 +/- 3.5 (p less than 0.025) in control subjects. This study shows that recombinant interferon beta improves suppressor function in humans, an effect that is particularly significant in progressive MS.

Adult↗
PubMed1987

A system for rapid DNA sequencing with fluorescent chain-terminating dideoxynucleotides.

A DNA sequencing system based on the use of a novel set of four chain-terminating dideoxynucleotides, each carrying a different chemically tuned succinylfluorescein dye distinguished by its fluorescent emission is described. Avian myeloblastosis virus reverse transcriptase is used in a modified dideoxy DNA sequencing protocol to produce a complete set of fluorescence-tagged fragments in one reaction mixture. These DNA fragments are resolved by polyacrylamide gel electrophoresis in one sequencing lane and are identified by a fluorescence detection system specifically matched to the emission characteristics of this dye set. A scanning system allows multiple samples to be run simultaneously and computer-based automatic base sequence identifications to be made. The sequence analysis of M13 phage DNA made with this system is described.

Automation↗
PubMed1987

Psychotropic drug use with successful and unsuccessful community placed developmentally disabled groups.

While psychotropic drug use data have been reported for public residential facilities (PRF) and community residential facilities (CRF), no data have been reported for individuals discharged from PRFs and CRFs, especially with respect to how such usage relates to successful and unsuccessful placement. This study reports psychotropic drug use at the time of PRF discharge, at CRFs for successful placements, upon PRF readmission for unsuccessful placements, and factors related to successful and unsuccessful CRF placements.

Adult↗
PubMed1986

The AHEC library program and consortia development in California.

A brief history of the first Area Health Education Center (AHEC) Library Program in California is presented, with a description of methodology and results. The goals of this program were to develop and improve hospital library resources and services, to train hospital library personnel, and to promote resource sharing in a medically underserved area. The health sciences library consortium that evolved became a model for the ten other library consortia in the state. Based on AHEC's twelve years' experience with consortia, from 1973 to 1985, recommendations are made as to size, composition, leadership, outside funding, group participation, publicity, and linkages.

Area Health Education Centers↗
PubMed1979

Effects of response-contingent clock stimuli on behavior maintained by intravenous codeine in the rhesus monkey.

Response-contingent brief presentations of clock stimuli differentially correlated with food availability altered rates of codeine-maintained lever pressing. Rhesus monkeys performed under a two lever multiple schedule: Multiple fixed interval clock 5 min variable interval 2 min. Different colored lights were presented during successive 75 sec period of the fixed-interval clock component. Lever pressing under the FI Clock schedule was maintained by presentation of 1 g Noyes pellets, and lever pressing under the VI schedule by 0.05 mg/kg infusions of codeine PO4. Characteristic schedule-controlled performance developed in both schedule components. When the clock stimulus from the first or the final period of the FI Clock schedule was presented contingent upon completion of a short fixed ratio of responses during the variable-interval schedule component, the first clock stimulus decreased and the final clock stimulus increased rates of codeine-maintained lever pressing. Neither the first nor the final clock stimulus altered the frequency of codeine injection. The effect of each clock stimulus was accentuated by increasing the duration of stimulus presentation and by decreasing the response requirement for stimulus illumination. These rate-altering effects of the clock stimuli were most pronounced when different reinforcers were presented in the two components of the multiple schedule when either food or intravenous codeine injection was available under both components of the multiple schedule, response-contingent clock stimulus presentation did not alter response rates under the VI schedule.

Animals↗
PubMed1977

Visual complaints and binocular function in bilaterally aphakic persons with cataract glasses.

Seventy-one consecutive patients who underwent operation for senile cataract in both eyes during the period 1969-1973 were examined and questioned about visual complaints an average of 18 months after being fitted with cataract spectacles. In the distance situation none had complaints, either reported spontaneously or after questioning. Except for a few immobile patients, all could manage on their own in the street and on stairs. In the near situation 16 of the 71 patients had permanent alternating or intermittent exotropia which, however, gave rise to diplopic complaints in only two. The diplopia in these two patients disappeared after the glasses had been decentered. On questioning, complaints of diplopia could be elicited in another 5 patients. Investigation of sensory binocular function using Titmus' sterotest showed that 35 of the 71 patients could manage the test at the level 40 inches/arc. Division of the material into two groups by duration of monocular visual function during the development of the cataract and during the period between the operations on the two eyes, disclosed that this factor was of no importance to the postoperative motor and sensory binocular function.

Aged↗