Biomedical subjects
R Stark
Publications and source records attributed to R Stark.
Classical swine fever virus: independent induction of protective immunity by two structural glycoproteins.
To study which proteins of classical swine fever virus (CSFV) are able to confer protective immunity in swine, N-terminal autoprotease, viral core protein, and the three structural glycoproteins were expressed via vaccinia virus recombinants (VVR). CSFV proteins synthesized in cells infected with VVR showed migration characteristics on sodium dodecyl sulfate gels identical to those of their respective CSFV counterparts. Apparently authentic dimerization of the recombinant glycoproteins was observed. The glycoproteins E0 and E2 were detected on the surfaces of VVR-infected cells. In protection experiments, swine were immunized with the different VVR, and the generation of humoral immune response was monitored. Only animals vaccinated with VVR expressing E0 and/or E2 resisted a lethal challenge infection with CSFV. Glycoprotein E0 represents a second determinant for the induction of protective immunity against classical swine fever.
Ethics of nursing and midwifery: responding to change.
Nurses and midwives are taking an increasing interest in ethical matters in their professions. Although the conditions in which they work vary immensely and are undergoing rapid change, it is possible to detect certain basic notions of patient care which transcend cultural, socioeconomic and technological differences.
The expression of cytokine and cytokine receptor genes in long-term bone marrow culture in congenital and acquired bone marrow hypoplasias.
A number of cytokines have been shown to have stimulatory activity on multipotent haematopoietic precursors. These include kit ligand (KL), interleukins (IL) 1, 3 and 6 and granulocyte macrophage-colony stimulating factor (GM-CSF). Using reverse transcriptase/polymerase chain reaction method (RT/PCR) we have examined the expression of these cytokines, the c-kit and IL-6 receptors, in long-term bone marrow culture (LTC) adherent layer cells in human bone marrow hypoplasia syndromes. Disorders studied include Fanconi's anaemia (FA, n = 16), idiopathic aplastic anaemia (AA, n = 11), Seckel's syndrome (n = 2), dyskeratosis congenita (n = 2), Shwachman-Diamond syndrome (n = 1), thrombocytopenia with absent radii syndrome (n = 1), acquired amegakaryocytosis (n = 1), paroxysmal nocturnal haemoglobinuria (n = 1) and acquired agranulocytosis (n = 1). IL-6 and GM-CSF expression appeared reduced in most patients with FA, suggesting that impaired production of these cytokines may contribute to the bone marrow failure seen in most patients with FA. In contrast, abundant IL-6 and GM-CSF expression were seen in most patients with AA when compared with the FA group and controls; these may be mediators of a stromal response in this disorder. No obvious differences were seen between the different patients' groups and controls in expression of the other cytokines or cytokine receptors studied.
Rearrangement of viral sequences in cytopathogenic pestiviruses.
Two cytopathogenic isolates of bovine viral diarrhea virus (cpBVDV) have been analyzed. For both viruses two regions of their genomic RNAs were found to be duplicated and rearranged. The viral genomes contain a small duplicated element (SD) derived from the genomic 5' end far downstream of its original context. This sequence is followed by a larger duplication which encompasses the region coding for the protein p80(LD), a molecular marker for cpBVDV. The SD element codes for the viral protease p20. In the case of the viruses analyzed here the aminoterminus of p80 is generated by autoproteolytic removal of the preceding SD-encoded protease. For one of the cpBVDV isolates a specific fusion protein (p28) could be identified which is composed of p20 and part of p10, another viral protein. Molecular characterization of the respective noncytopathogenic counterpart revealed that duplication and rearrangement of sequences as well as the expression of p28 and p80 are specific for the cytopathogenic virus.
Proteins encoded in the 5' region of the pestivirus genome--considerations concerning taxonomy.
The first protein encoded within the pestivirus open reading frame is a nonstructural protein which removes itself from the polyprotein by autoproteolytic cleavage. The following nucleocapsid protein ends just before a putative signal sequence preceding three glycosylated proteins. All three glycoproteins are part of the viral envelope and exist in the form of disulfide-linked dimers. Pestiviruses have recently been reclassified as members of the family Flaviviridae which now comprises three genera, namely flavivirus, hepatitis C virus group and pestivirus. All members of the family have certain characteristics in common like the overall genome organization and the strategy of gene expression. Major differences exist, however, between the genera; the most obvious ones concern proteins encoded in the 5' region of the respective genomes.
A second envelope glycoprotein mediates neutralization of a pestivirus, hog cholera virus.
Several monoclonal antibodies (MAbs) raised against hog cholera virus (HCV) reacted with the HCV structural glycoprotein gp44/48 and neutralized the virus. The presence of HCV gp44/48 on the viral surface was directly demonstrated by immunogold electron microscopy. Eight anti-HCV gp44/48 MAbs were tested by immunoperoxidase assay against a panel of pestivirus strains. Each MAb showed a distinct pattern of reactivity with HCV strains. It is suggested that the MAbs are well suited for epidemiological investigations of HCV outbreaks.
Developmental changes in sequential activation of laryngeal abductor muscle and diaphragm in infants.
In animals and human adults, upper airway muscle activity usually precedes inspiratory diaphragm activity. We examined the interaction of the posterior cricoarytenoid muscle (PCA), which abducts the larynx, and the diaphragm (DIA) in the control of airflow in newborn infants to assess the effect of maturation on respiratory muscle sequence. We recorded tidal volume, airflow, and DIA and PCA electromyograms (EMG) in 12 full-term, 14 premature, and 10 premature infants with apnea treated with aminophylline. In most breaths, onset of PCA EMG activity preceded onset of DIA EMG activity (lead breaths). In all subjects, we also observed breaths (range 6-61%) in which PCA EMG onset followed DIA EMG onset (lag breaths). DIA neural inspiratory duration and the neuromechanical delay between DIA EMG onset and inspiratory flow were longer in lag than in lead breaths (P < 0.05 and P < 0.01, respectively). The frequency of lag breaths was greater in the premature infants [33 +/- 4% (SE)] than in either the full-term infants (21 +/- 3%, P < 0.03) or the premature infants with apnea treated with aminophylline (16 +/- 2%, P < 0.01). We conclude that the expected sequence of onset of PCA and DIA EMG activity is frequently disrupted in newborn infants. Both maturation and respiratory stimulation with aminophylline improve the coordination of the PCA and DIA.
Hematopoietic progenitors cells in cord blood.
Human umbilical cord blood was evaluated as an alternative to bone marrow as a source of stem cells for hematopoietic transplantation. In order to define an optimal collection procedure, we have studied the parameters that influence the collection, handling and storage of cord blood. We have attempted to correlate the quality of the samples with obstetrical and neonatal parameters. Using culture techniques we have studied the long term viability of the cells. Cell separation was also investigated. Our results suggest that most of the sample collected could be suitable for transplantation, in term of progenitors. However the observed variability between samples suggest that an efficient control of the quality of the samples is important.
Locally advanced paranasal sinus and nasopharynx tumors treated with hyperfractionated radiation and concomitant infusion cisplatin.
Fourteen patients with paranasal sinus complex and nasopharynx tumors were treated at State University of New York Health Science Center at Brooklyn (Brooklyn, NY) with a regimen of split-course hyperfractionated radiation (120 cGy/fraction) and concomitant cisplatin infusion (5 to 7 mg/m2/24 hours). All of the patients had T4 tumors or massively recurrent disease with base of skull or facial bone involvement. Twelve patients were treated with curative intent receiving total doses of 6000 to 6960 cGy (modal 6750 cGy), whereas two patients were treated with less than 5000 cGy as palliation. Eleven of the 12 patients (92%) achieved a complete response, and 7 of 12 (58%) are alive at 35 to 72 months (mean, 47 months). Five patients are alive with no evidence of disease, and two with a local recurrence. Three patients died of distant disease, and two died from a local recurrence. When the response to treatment was analyzed based on tumor volume and radiation dose, only two of nine lesions measuring between 4 to 10 cm failed locally. The two palliative patients had almost complete local clearance of the disease but died at 2 and 8 months, respectively. In nine patients, the eye or optic nerve was included in the treatment field and received between 2000 to 6960 cGy. Only one of these nine patients had ophthalmic complication and this was confined to the cornea.
Structural proteins of hog cholera virus expressed by vaccinia virus: further characterization and induction of protective immunity.
A cDNA fragment covering the genomic region that encodes the structural proteins of hog cholera virus (HCV) was inserted into the tk gene of vaccinia virus. Expression studies with vaccinia virus/HCV recombinants led to identification of HCV-specific proteins. The putative HCV core protein p23 was demonstrated for the first time by using an antiserum against a bacterial fusion protein. The glycoproteins expressed by vaccinia virus/HCV recombinant migrated on sodium dodecyl sulfate-gels identically to glycoproteins precipitated from HCV-infected cells. A disulfide-linked heterodimer between gp55 and gp33 previously detected in HCV-infected cells was also demonstrated after infection with the recombinant virus. The vaccinia virus system allowed us to identify, in addition to the heterodimer, a disulfide-linked homodimer of HCV gp55. The vaccinia virus/HCV recombinant that expressed all four structural proteins induced virus-neutralizing antibodies in mice and swine. After immunization of pigs with this recombinant virus, full protection against a lethal challenge with HCV was achieved. A construct that lacked most of the HCV gp55 gene failed to induce neutralizing antibodies but induced protective immunity.
Hog cholera virus: molecular composition of virions from a pestivirus.
Virions from hog cholera virus (HCV), a member of the genus Pestivirus, were analyzed by using specific antibodies. The nucleocapsid protein was found to be a 14-kDa molecule (HCV p14). An equivalent protein could also be demonstrated for virions from another pestivirus, bovine viral diarrhea virus. The HCV envelope is composed of three glycoproteins, HCV gp44/48, gp33, and gp55. All three exist in the form of disulfide-linked dimers in virus-infected cells and in virions; HCV gp44/48 and gp55 each form homodimers, whereas gp55 is also found dimerized with gp33. Such complex covalent interactions between structural glycoproteins have not been described so far for any RNA virus.
Genomic localization of hog cholera virus glycoproteins.
A polyspecific antiserum has been used to identify four different glycoproteins in hog cholera virus (HCV)-infected cells termed gp55, gp48, gp44, and gp33 (Rümenapf et al, 1989, Virology 171, 18-27). Fusion proteins containing parts of the putative HCV-encoded glycoproteins were expressed in bacteria and served for the preparation of specific antibodies. These were used in radioimmunoprecipitation assays which revealed that gp48 and gp44 most likely share a common protein backbone. The order of the glycoproteins on the HCV genome was determined as follows: NH2-gp44/gp48-gp33-gp55-COOH.
Bedside blood filtration and risk of thrombosis.
Explore the source record for details and available documents.
Pestivirus glycoprotein which induces neutralizing antibodies forms part of a disulfide-linked heterodimer.
Neutralizing monoclonal antibodies directed against hog cholera virus (HCV) precipitated two HCV-encoded glycoproteins, HCV gp55 and HCV gp33. Immunoassay with bacterial fusion proteins and Western immunoblotting with extracts from infected cells revealed that the antibodies recognized only HCV gp55. Coprecipitation of HCV gp33 was shown to be due to intermolecular disulfide bridges. One of the antibodies also reacted with the major glycoprotein of another pestivirus, bovine viral diarrhea virus (BVDV). The analogous BVDV glycoproteins exhibited a distribution of cysteine residues which was almost identical to that of HCV gp55 and gp33. The two BVDV glycoproteins were also linked by disulfide bridges.
Peripheral blood T cell activation after radioiodine treatment for Graves' disease.
Radioiodine therapy for Graves' thyrotoxicosis produces a rise in thyroid autoantibodies in the first three months after treatment, but little is known of its effects on T cells. We have therefore followed the changes in T cell subsets in sequential samples from 23 patients with Graves' disease treated with radioiodine, using dual-colour flow cytometry. In the first month after treatment there was a significant rise in activated T cells, identified by the markers HLA-DR (la) and CDw26/Ta1 (p less than 0.025 in both cases). CD45RO-positive T cells, which are the primed population containing memory cells, also increased (p less than 0.025), but there was no change in CD45R-positive, resting T cells or in the CD4 to CD8 (helper to cytotoxic/suppressor) ratio. Vicia villosa-binding T cells, containing the contrasuppressor population, showed a more variable response, but the trend was to an overall increase from pre-treatment values (p less than 0.025). The changes did not appear to be related to antithyroid drug treatment, since they were seen irrespective of whether patients continued such therapy. These results suggest that T cell activation and enhanced contrasuppressor activity may in part be responsible for the rise in autoantibodies after radioiodine. The T cell changes could also contribute to the worsening of ophthalmopathy seen in some radioiodine-treated patients.
A TAFE strategy for biotechnology skills training.
The outline of a strategy for training technicians who will undertake biotechnology-oriented tasks as employees is the focus of this review. Technical and Further Education (TAFE) in Western Australia has recently restructured electives offered in certificate and diploma courses of Applied Science. The aim of restructuring was to allow a broader choice catering for specialized streams. With a few additions it would be possible to list a set of biotechnology options for technicians specializing in this area. After identifying employers in Western Australia, data on technician employment characteristics and training needs was gathered through a survey and used to formulate a future development strategy. In the past little attention has been given anywhere in Australia to the training needs of this group. The availability of such appropriately trained employees will increasingly be recognized as a vital link in the success of any biotechnology enterprise.
Nurses bring primary health care to industrial workers.
Progress in bringing health care to the workplace lags considerably behind progress in bringing health care to where people live. Experience in Botswana shows that the family nurse practitioner--a registered nurse midwife with one year of post-basic training--can provide useful preventive and curative services to people in their places of work.