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Biomedical subjects

E D Johnson

Publications and source records attributed to E D Johnson.

At least 37 records · Page 2Linked to original sources
PubMed1990

Biosynthesis, cDNA and amino acid sequences of a precursor of conglutin delta, a sulphur-rich protein from Lupinus angustifolius.

The biosynthesis of conglutin delta has been studied in developing cotyledons of Lupinus angustifolius L. Precursors of conglutin delta formed the major sink for [35S]-cysteine incorporated by developing lupin cotyledons, and these precursors were rapidly sequestered into the endoplasmic reticulum. The sequence of a cDNA clone coding for one such precursor of conglutin delta was determined. The structure of the precursor polypeptide for conglutin delta predicted from the cDNA sequence contained an N-terminal leader peptide of 22 amino acids directly preceding a subunit polypeptide of Mr 4520, together with a linking region of 13 amino acids and a subunit polypeptide of Mr 9558 at the C-terminus. The amino acid sequence predicted from the cDNA sequence showed minor variations from that established by sequencing of the protein purified from mature dried seeds (Lilley and Inglis, 1986). These were consistent with the existence of a multi-gene family coding for conglutin delta. Comparison of the sequences of conglutin delta with those of other 2S storage proteins showed that the cysteines involved in internal disulphide bridges between the mature subunits of conglutin delta, were maintained throughout this family of proteins but that little else was conserved either at the protein or DNA level.

Amino Acid Sequence↗
PubMed1989

Computer-assisted instruction in cancer for third-year medical students using the Physician Data Query (PDQ) system.

During the third-year medicine clerkship, students were instructed in online computer Physician Data Query (PDQ) searches. Each student completed computer searches in at least one of five tumor topics. Students assigned to selected tumor topics performed significantly better on test questions in their assigned topic as compared to the scores of students who were not assigned that topic. Although students were encouraged to use the PDQ ad libitum, within three months of completing the clerkship, only 22 students (20%) had conducted additional searches. We conclude that PDQ instruction may enhance students' knowledge about cancer. Student instruction can be effectively completed with minimal computer time. The results from our program evaluation and the limited student use following completion of the clerkship suggest that we should identify another user group, such as senior housestaff, to generate greater interest and more frequent use of the PDQ.

Clinical Clerkship↗
PubMed1989

Isolation and Characterization of Protein Bodies in Lupinus angustifolius.

Using Nycodenz, a novel density gradient medium, we isolated intact protein bodies from developing seeds of Lupinus angustifolius L. (cultivar Unicrop) and achieved excellent separation from the endoplasmic reticulum, mitochondria, and other organelles. The distribution of the storage protein conglutin-beta was taken as evidence that up to 96% of the protein bodies remained intact on the gradients and banded at 1.25 grams per milliliter. The protein bodies also contained the three other abundant proteins present in L. angustifolius seeds: conglutins-alpha, -gamma, and -delta. Pulse labeling experiments were carried out to determine the site of proteolytic processing of conglutin-alpha, a legumin-like 11Svedberg unit storage protein. Cotyledons aged either 33 or 40 days after flowering were pulsed with [(3)H]leucine. Protein bodies obtained from the cotyledons aged 33 days after flowering contained only the labeled precursors of conglutin-alpha with molecular weights 85,000, 72,000, and 64,000, even after a 4 hour chase of the radioactivity. Protein bodies obtained from the cotyledons aged 40 days after flowering contained the same radioactive precursors if the tissue had been pulsed for 2 hours, and the processing products of these precursors when the tissue had been chased for 4 hours. These studies confirm that the subcellular location of proteolytic cleavage of this legumin-like protein is the protein body, that this activity is detected only in protein bodies from lupin seeds aged between 33 and 40 days of seed development after flowering and that protein bodies from seeds younger than this contain only unprocessed conglutin-alpha.

Journal Article↗
PubMed1989

Lateral supporting ligament of the distal phalanx.

A 49-year-old woman complained of 3 months of constant aching pain deep to the ingrown medial nail margin of her right hallux that was unaffected by shoe wear. Physical examination disclosed no purulence, discoloration, or obvious acute inflammation; an incurved medial nail plate was seen. There was mild chronic thickening of the medial nail fold. Tenderness was maximal 2 to 3 mm plantar to the medial edge of the nail. By roentgenogram, bony projections were seen arcing from the distal phalangeal tuft and the proximal metaphyseal flare toward each other. This was considered to be a "normal" radiological variant. A partial medial onychectomy and matricectomy (Winograd procedure) was performed. Further dissection 1 to 2 mm deeper along the medial phalangeal border revealed a 1-mm wide longitudinal ligament extending from the phalangeal distal tuft to the proximal metaphyseal flare. Bony projections and ligament were excised. The wound healed satisfactorily, and symptoms ceased.

Female↗
PubMed1989

Teaching human genetics in biochemistry by computer literature searching.

We describe a new user-intense-learning experience that incorporates the teaching of clinical and research applications of human genetics in biochemistry while training first-year medical students to develop skills in computer access to the literature. Human genetics was incorporated into the biochemistry curriculum by providing each student with experience in on-line literature searching in MEDLINE, using Grateful Med, in order to write an abstract about a specific inherited biochemical disorder. We stressed the need for the students to obtain current information in order to understand and interpret the rapidly changing field of human genetics. We taught the students that the most efficient method of obtaining such information was by searching the medical literature via computer.

Biochemistry↗
PubMed1989

In search of applications of nursing theories: the Nursing Citation Index.

Cited author searches were conducted in Nursing Citation Index to determine its utility in locating clinical studies that apply the conceptual frameworks of Dorothea Orem, Callista Roy, Martha Rogers, Betty Neuman, and Dorothy Johnson. Fully 75 percent of the relevant papers would have been missed by a conventional subject/textword search in the MEDLINE or CINAHL databases. Had Nursing Citation Index not been available, only 22 percent of relevant papers could have been retrieved by cited author searches of Social Science Citation Index. In summary, Nursing Citation Index provides an important indexing link between nursing theory and nursing research.

MEDLARS↗
PubMed1987

[Current serologic data on viral hemorrhagic fevers in the Central African Republic].

During the years 1984-1985, 1,528 serum samples were taken through out the CAR. Of these sera, 319 (20.8%) contained anti-Filoviridae antibodies (Ebola, Marburg). This figure is higher than those found in Cameroon, Sudan, Gabon and Zaïre. Three zones of the country are particularly exposed, the North-East where the population is in the contact with Sudan Ebola, the South-East where it is in contact with Zaïre Ebola, and the South-West where it is in contact with Sudan Ebola. The authors believe that there could exist either a Central African Ebola strain or an Ebola-Like less pathogenic virus which is responsible for cross reactions. Results concerning Rift Valley Fever virus, Congo virus and Lassa virus seem less interesting. However RVF and Congo strains were isolated.

Arenaviridae↗
PubMed1986

A complication of cleansing enema: retained protective shield of the enema tip.

A retained enema tube sheath was encountered in 4 outpatients who underwent preparation for barium enema. This object can be detected on a plain abdominal roentgenogram, but is more readily apparent as an intraluminal foreign body during barium enema examination. We suggest that a prominent warning to remove the sheath before taking a cleansing enema be attached to the enema tip.

Barium Sulfate↗
PubMed1985

Biosynthesis and processing of legumin-like storage proteins in Lupinus angustifolius (lupin).

Synthesis, secretion and post-translational proteolysis of the storage proteins in cotyledons of Lupinus angustifolius L. (lupin) have been examined in vivo and in vitro by using a combination of pulse-chase experiments with [3H]- or [35S]-labelled amino acids, subcellular fractionation and cell-free translation from poly(A)+ (polyadenylylated) RNA or membrane-bound polyribosomes. Related polypeptides were identified by immunoprecipitation, separation on sodium dodecyl sulphate/polyacrylamide gels and fluorography. The synthesis and processing of two proteins were compared. Conglutin alpha, the 11 S protein, was found as a family of precursor polypeptides of Mr 68000-88000 when translated from poly(A)+ RNA under conditions where signal segments were not cleaved, and Mr 64000-85000 both when sequestered into the endoplasmic reticulum and when accumulated in the protein bodies. Pulse-chase labelling showed that cotyledons from early stages of development were completely incapable of further proteolysis of these precursors. Nevertheless, in the same juvenile cotyledons, the precursors of the minor storage protein conglutin gamma, two polypeptides with Mr 50000-51000, were proteolytically cleaved to mature subunits of Mr 32000 and 17000 within 2 h. Further cleavage of the precursors of conglutin alpha into families of mature subunits of Mr 21000-24000 and 42000-62000 was detected in more mature cotyledons. A model is proposed which suggests that the mature subunits are produced by a single proteolytic cleavage of each of the three major precursors of conglutin alpha and also suggests that a close similarity exists between these subunits and those of other legumin-like proteins. The enzyme responsible for this cleavage, which appears at a specific stage in the middle of cotyledonary development, seems to be an integral part of the programmed developmental sequence in these pods.

Biological Transport↗
PubMed1984

Precursors of storage proteins in Lupinus angustifolius.

The proteins that are synthesized during differentiation and development in the cotyledons of Lupinus angustifolius L. were characterized both in situ and after purification. The proteins present in situ were separated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and subjected to 'Western'-blot analysis to identify immunologically related polypeptides. The major storage proteins of the lupin, conglutins alpha and beta, were both present in juvenile tissue only as higher Mr precursors. For conglutin beta, a family of at least three polypeptides of Mr 66 000-72 000 accumulated during the earliest phases of protein synthesis in the developing cotyledon (20-28 days after flowering). Later in development each of these polypeptides disappeared and there was the concurrent appearance in the cotyledon of the lower-Mr fragments characteristic of mature conglutin beta. For conglutin alpha, an equivalent family of precursor polypeptides of Mr 60 000-83 000 was detected. Multiple internal sites for proteolytic cleavage of all these precursors appeared to be present. However, processing of the precursors was sufficiently slow to allow them to accumulate to over 50% of total soluble protein in juvenile tissue. The precursors were purified by column chromatography under non-dissociating conditions and shown by ultracentrifugation to be multimeric proteins with Mr values in the range 150 000-200 000.

Electrophoresis, Polyacrylamide Gel↗
PubMed1983

Techniques of Online Citation Verification in NLM Databases.

This article is an exploration of techniques for identifying items in the health related literature using NLM system databases. Examples used are derived from reference desk and interlibrary loan files, but the techniques should be useful to any medical librarian who needs to verify a citation. A knowledge of NLM indexing practices and system commands is assumcd. Because of mace limitations the TOXLINE. TOXBACK74, TOXBACK65,AVLINE files have been omitted, but other bibliographic files and SERLINE are included. Tables designed for at-terminal use are presented.

Journal Article↗
PubMed1982

Ia antigens are the stimulating determinants in the syngeneic mixed lymphocyte reaction.

The murine syngeneic mixed lymphocyte reaction (sMLR) is a T cell proliferative response to self-antigens on non-T stimulator cells. The nature and specificity of the stimulating antigens was investigated using secondary MLR. Lymph node cells were stimulated in vitro by syngeneic spleen cells. After optimal proliferation occurred, the responding cell population was recovered and restimulated with spleen cells from mice of various haplotypes. The secondary response was found to be specific for the haplotype of the primary stimulator (a self-restricted response). The use of recombinant mice in the secondary stimulation localized the determinant to the I-A and/or I-E subregions of the major histocompatibility complex (MHC). This result was confirmed by the ability of monoclonal antibodies directed to the I-A or I-E subregion products to significantly inhibit the response while alloantiserum directed to products of the K or D regions had no effect.

Animals↗
PubMed1975

Functional heterogeneity of lymphocytic choriomeningitis virus-specfic T lymphocytes. I. Identification of effector amd memory subsets.

At varying intervals after immunizing infections of adult BALB/c mice with lymphocytic choriomeningitis (LCM) virus, splenic lymphocytes were tested for their ability to either elicit acute LCM or protect against lethal intracerebral LCM virus challenge when transferred to syngeneic recipients that were, respectively, virus carriers induced by cyclophosphamide-induced immunosuppression and normal susceptible mice. These lymphocytes were also assayed for their capacity to lyse, in vitro, LCM virus-infected BALB 3T3 cells labeled with 51Cr. Only lymphocytes obtained from donor mice between 6 and 8 days postimmunization significantly protected normal recipients from the development of lethal central nervous system (CNS) disease when transferred 18-24 h before virus challenge. At 10 days they were not protective even though their cytolytic activity in vitro either exceeded or approximated that of protective lymphocytes. The capacity to protect more closely corresponded with a period of virus-induced DNA synthesis in donor spleens as measured by the incorporation of [5--125I]-2'-DEOXYURIDINe. However, none of these cytolytically active lymphocyte populations were effective in mediating acute CNS disease when transferred to virus-carrier mice. In contrast, lymphocytes obtained 18 days or later after primary immunization, although having no protective capacity and exhibiting minimal cytolytic activity in vitro, were able to regularly produce acute disease in virus-carrier mice. The ablation by anti-theta-serum treatment of these in vivo and in vitro virus-specific immune functions established that the relevant lymphoid cells were T lymphocytes. Similarly, reconstitution of C3H times C57BL F1 adult mice, depleted of lymphocytes by thymectomy and lethal irradiation, with syngeneic day 8 immune donor lymphocytes rendered them resistant to the development of the carrier state after intracerebral virus challenge; reconstitution of such animals with nonimmune lymphocytes restored their ability to develop typical LCM. Collectively, these data indicate that immunogenic stimulation with LCM virus leads to the development of at least two different virus-specific T-lymphocyte subsets: (a) an early appearing transient effector population of cells and, perhaps, their immediate precursors whose generation requires the presence of virus, and (b) a stable memory population that appears well after virus clearance and which has little or not no cytolytic activity. The possible mechanism by which these functionally different subsets can influence the outcome of acute or chronic LCM virus infections is discussed.

Acute Disease↗