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Biomedical subjects

L J Lewandowski

Publications and source records attributed to L J Lewandowski.

At least 19 recordsLinked to original sources
PubMed1994

Selective attention skills of experienced sonar operators.

This study investigated the influence of sonar training and experience on the selective attention of experienced and inexperienced operators. The Stroop task was selected as a measure of general selective attention, similar in certain task requirements (attentional allocation) to sonar operation. Across two samples (ns = 32 and 36) and four repeated test sessions groups did not differ significantly in speed or accuracy of Stroop performance. The data suggest that experienced operators do not seem to have developed extraordinary attentional skills and that any attentional skills developed through sonar experience do not generalize to other tasks such as the Stroop.

Adult↗
PubMed1987

Neurodevelopmental outcome of preschool children born preterm with and without intracranial hemorrhage.

Thirty-five children who had been born preterm with and without intracranial hemorrhage and weighing less than or equal to 1500 g were followed prospectively to assess neurodevelopmental outcome. The 13 children with hemorrhage were inferior to the 22 without hemorrhage in terms of birthweight, Apgar scores, health complications at and after birth, neurological integrity at age five and several scales of the McCarthy Scales of Children's Abilities. The hemorrhage group performed significantly below the standardized mean on each of the McCarthy scales, whereas the group without hemorrhage performed below the mean only in Quantitative and Memory scores. The Bayley scales at one year were not clinically sensitive to hemorrhage, but were predictive of McCarthy General Cognitive Index scores at age five. A greater proportion of children with hemorrhage have had educational difficulties and have been included in alternative school programs. Preterm, very low-birthweight children, and particularly those with intracranial hemorrhage, are at high risk for motor, perceptual and cognitive defects which underlie learning difficulties.

Brain Damage, Chronic↗
PubMed1986

Monoclonal antibodies to bovine platelet factor 4: species interactions to platelets and megakaryocytes using indirect immunocytofluorescence.

Murine monoclonal antibodies (mAb) were raised to a purified product of bovine PF-4, a 9,500 dalton protein with heparin neutralization activity comparable to that of human PF-4. Using a non-radioactive slide immunoenzymatic assay, four major classes of mAb could be identified when comparisons were made between purified antigens of PF-4 and beta-TG-like protein from both bovine and human species. Type 1 cross-reacted with all four antigens; type 2 reacted with PF-4s; type 3 reacted with only bovine PF-4 and beta-TG-like protein; and type 4 reacted only with bovine PF-4. Differences in immunoreactivities of types 1, 2 and 3 were retained throughout the growth of succeeding clones and in ascitic fluids. Using a modified factor Xa, S-2222 chromogenic substrate-heparin inhibition assay, no mAb was found to block PF-4's ability to neutralize heparin. mAbs representative of types 1, 2 and 3 were successfully raised in stable cell lines from at least second generation clones. These were purified with protein A agarose and found to be IgG1. By indirect immunocytofluorescence a purified type 2 mAb, 2E7, was found to specifically stain granules of human platelets and megakaryocytes, as well as masses (putative platelets within late stage megakaryocytes) without staining other cellular types in either bone marrow or peripheral blood. Species comparisons displayed positive staining for human, rat, and rabbit platelets and megakaryocytes, and negative staining for mouse, guinea pig and dog platelets and megakaryocytes. It seems likely that mAb, 2E7, is directed against an epitope, common to PF-4 of bovine, human, rabbit and rat.

Animals↗
PubMed1984

The Symbol Digit Modalities Test: a screening instrument for brain-damaged children.

28 brain-damaged males ranging in age from 8 to 16 yr. were compared with 28 nondamaged matching controls on their Symbol Digit Modalities Test performance. The damaged group performed significantly more poorly, and 75% of the subjects scored more than .5 z score below their matched controls. The results suggest that this brief and objective test can be used to screen brain-damaged children when their performance is compared to that of a control group or the normative group.

Adolescent↗
PubMed1976

Cell-mediated cytotoxicity against murine cells infected with 6/94 virus, a parainfluenza type 1 isolate from multiple sclerosis brain tissue.

Maximum cytotoxicity to parainfluenza type 1 viral determinants occurs on day 5 post-immunization in mice with and without preexisting anti-6/94 virus antibody. Animals with preexisting anti-6/94 serum antibody, however, exhibited a markedly higher cytotoxic response. Syngeneic, allogeneic, and xenogeneic virus-infected cells induce virus-specific cytotoxicity, but only infected cells histocompatible with the effector cells can serve as susceptible target cells. The effector cell is a T cell, and hence cytotoxicity is thymus dependent. Coincident with the maximum cytotoxic activity on day 5 is the occurrence of pathological lesions, the sites of which are dependent on the route of inoculation.

Amino Acids↗
PubMed1975

Detection of cellular hypersensitivity among multiple sclerosis (MS) patients to 6/94 virus; a parainfluenza type 1 isolate from MS brain tissue.

Multiple sclerosis (MS) patients and normal subjects were tested for cellular hypersensitivity, using the leukocyte migration inhibition test LMI), to a parainfluenza-1-virus (6/94), previously isolated from brain biopsy tissue of an MS patient. The response of MS patients as a group was not greater than that of normals to 6/94, but a significant increase in the response was observed among selected patients in the early active and chronic advanced stages of the disease. MS patients, however, did not differ from normal subjects in their cell response to Sendai virus, a similar parainfluenza type 1 virion used for comparison.

Acute Disease↗
PubMed1974

Isolation of the major viral glycoprotein and a putative precursor from cells transformed by avian sarcoma viruses.

Immune precipitation with a monospecific antiserum was employed to study the synthesis of the major viral glycoprotein gp85. Labeled gp85 was detectable by polyacrylamide gel electrophoresis of immune precipitates prepared from lysates of transformed cells which had been labeled for long term with radioactive amino acid or fucose. When immune precipitates were prepared from lysates of cells pulse-labeled with radioactive amino acid, the bulk of the precipitated counts did not appear in gp85 but in a heterogeneous protein fraction with a mean molecular weight of approximately 70,000; this fraction has been designated p70. If, however, the pulse label was followed by incubation of the cells in medium containing excess unlabeled amino acid, the bulk of the precipitated counts comigrated with gp85. Similar pulse-labeling experiments with radioactive fucose and glucosamine suggested that p70 represents incompletely glycosylated precursor to gp85.

Alpharetrovirus↗
PubMed1974

Analysis of a viral agent isolated from multiple sclerosis brain tissue: characterization as a parainfluenzavirus type 1.

A virus originally isolated from cell cultures obtained by lysolecithin-induced fusion of human multiple sclerosis brain cells with CV-1 cells has been analyzed for its antigenic, RNA, and polypeptide compositions, and for selective biological properties. Our findings establish that this isolate, designated 6/94 virus, contains a 50S RNA genome and is, as yet, indistinguishable from Sendai virus in its antigenic and total polypeptide compositions. Despite these similarities, the 6/94 and Sendai viruses differ in certain phenotypic properties. 6/94 virus is markedly less cytocidal for chick fibroblasts, especially at 37 C and, after beta-propiolactone inactivation, it possesses a greater capacity for cell fusion and a lower toxicity than does comparably treated Sendai virus. In addition, 6/94 virus shows greater hemolytic activity.

Animals↗
PubMed1972

Comparison of the structure and polypeptide composition of three double-stranded ribonucleic acid-containing viruses (diplornaviruses): cytoplasmic polyhedrosis virus, wound tumor virus, and reovirus.

Iodination of reovirus, cytoplasmic polyhedrosis virus (CPV), and wound tumor virus (WTV), and their respective subviral forms, followed by analysis of the labeled polypeptides by using polyacrylamide gel electrophoresis, has been used to compare the protein contents of these three diplornaviruses. This approach, when combined with electron microscopy and buoyant density determinations, appears capable of localizing individual polypeptides in some of the viral and subviral forms. CPV (p = 1.435 g/cm(3)) seems to resemble reovirus cores (p = 1.440 g/cm(3)) in both ultrastructure and polypeptide composition. CPV is composed of five polypeptides with molecular weights of about 151,000, 142,000, 130,000, 67,000, and 33,000. The polyhedral matrix, which in nature encapsulates the virions, is, in turn, composed mainly of two polypeptide species with molecular weights of about 30,000 and 20,000, and several minor proteins. The proteins of WTV consist mainly of four species of polypeptide with molecular weights of about 156,000, 122,000, 63,000, and 44,000, and several minor components. These molecular weight determinations are consistent with the hypothesis that, as has been suggested for reovirus, the viral proteins of CPV and WTV seem to be coded for by monocistronic mes senger RNA molecules transcribed from distinct segments of the double-stranded RNA viral genomes.

Centrifugation, Density Gradient↗
PubMed1972

Comparison of the 3' termini of discrete segments of the double-stranded ribonucleic acid genomes of cytoplasmic polyhedrosis virus, wound tumor virus, and reovirus.

The 3' terminal nucleosides of the isolated components of double-stranded ribonucleic acids of reovirus, wound tumor virus, and cytoplasmic polyhedrosis virus were determined by labeling with tritiated sodium borohydride. All wound tumor virus and cytoplasmic polyhedrosis virus components appear to contain approximately equal amounts of U(OH) and C(OH) termini. Reovirus segments have essentially only C(OH) termini.

Adenosine↗
PubMed1971

Characterization of the genome of cytoplasmic polyhedrosis virus.

It is possible to oxidize in situ the 3'-terminals of the double-stranded ribonucleic acid (RNA) contained in structurally intact cytoplasmic polyhedrosis virus. The number of 3'-terminals subsequently found by reduction with tritiated sodium borohydride was equivalent to the number observed in RNA first isolated from the virus and then oxidized and reduced. The viral RNA appears to occur in 10 distinct polynucleotide segments present in equimolar amounts.

Borohydrides↗