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Biomedical subjects

M Ferguson

Publications and source records attributed to M Ferguson.

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

Differences in conformation of type 3 poliovirus antigenic sites on non-infectious empty particles and infectious virus.

A panel of monoclonal antibodies which react with empty non-infectious type 3 poliovirus particles (C antigen) but not infectious virus (D antigen) were characterized for their reactivity with C antigen particles derived from neutralization-resistant virus strains which had single amino acid substitutions at each of the antigenic sites. Antibodies were identified which failed to bind to variant viruses with modifications at each of antigenic sites 2b, 3b and 4 indicating that the same amino acid sequences involved in the neutralization of infectious virus are also present on the surface of non-infectious particles but in different configurations.

Amino Acid Sequence↗
PubMed1990

Assessment of potentially avoidable perinatal mortality in a regionalized program.

To obtain data regarding factors that influence perinatal mortality, a comprehensive perinatal mortality review project was prospectively developed and implemented. The resulting data cover a 21-month period and include all perinatal mortality at two perinatal centers and ten community hospitals. For each case an assessment of potential avoidability was made using the following definition: if any factor was identified that might have altered the outcome, the case was judged potentially avoidable. All other mortality was classified as either unavoidable or undetermined (if sufficient data were not available). During the review period there were a total of 26,937 live births and 591 cases of perinatal mortality. We conclude that: (1) meaningful analysis of factors affecting perinatal mortality data can be obtained by review of all deaths using a standardized classification; (2) in 21% of perinatal mortality at least one potentially avoidable factor could be identified that might have altered the outcome, while 74% was unavoidable and 5% undetermined; and (3) implementation of the review process enabled the reviewers to recognize patterns of potentially avoidable perinatal deaths.

Birth Weight↗
PubMed1989

Monoclonal antibodies for detection of occult carcinoma cells in bone marrow of breast cancer patients.

Metastases develop in 30% to 40% of patients with operable breast cancer. Investigators have reported on the detection of occult micrometastases in bone marrow using an antibody to epithelial membrane antigen (EMA) and have since reported prognostic significance for these antibody-detected cells. In this study, two anti-cytokeratin monoclonal antibodies (35 beta H11 and 34 beta E12) were used to examine bone marrow specimens from patients with breast cancer. The technique was first studied in a test system in which human or monkey bone marrow was seeded with MCF-7 cells, and was determined to be sensitive enough to detect fewer than one cancer cell in 10(4) hematopoietic cells. An immunoglucose oxidase method was used for patient specimen antibody localization and was found to be free of false-positive staining. Marrow specimens from 25 patients with breast cancer of various stages were examined. No correlation with disease stage was observed. We conclude that the technique is feasible, but prognostic import remains to be determined.

Antibodies, Monoclonal↗
PubMed1989

An engineered poliovirus chimaera elicits broadly reactive HIV-1 neutralizing antibodies.

The Sabin type 1 vaccine strain of poliovirus is probably the safest and most successful live-attenuated vaccine virus used in humans. Its widespread use since the early 1960s has contributed significantly to the virtual eradication of poliomyelitis in developed countries. We have reported previously the construction of an intertypic antigen chimaera of poliovirus, based on the Sabin 1 strain, and proposed that this virus could be modified to express on its surface antigenic determinants from other pathogens. We describe here the construction and characterization of a poliovirus antigen chimaera containing an epitope from the transmembrane glycoprotein (gp41) of human immunodeficiency virus type 1 (HIV-1). In antibody absorption experiments, the virus chimaera inhibited neutralization of HIV-1 by antipeptide monoclonal antibodies specific for the gp41 epitope and significantly reduced the group specific neutralizing activity of HIV-1-positive human sera. Rabbit antisera raised by subcutaneous injection of the polio/HIV chimaera in adjuvant was shown to be specific for HIV-1 gp41 in peptide-binding assays and by western blotting. Moreover, the antisera neutralized a wide range of American and African HIV-1 isolates and also inhibited virus-induced cell fusion. Monoclonal antibodies against the HIV-1 derived regions of the chimaera also neutralized HIV-1. These results establish the potential of using poliovirus for the presentation of foreign antigens and suggest that Sabin 1 poliovirus/HIV chimaeras could offer an approach to the development of an HIV vaccine.

Amino Acid Sequence↗
PubMed1989

A collaborative study to establish the International Reference Reagent for hepatitis B vaccine containing plasma-derived hepatitis B surface antigen.

A collaborative study was conducted to establish a suitable international reference reagent for hepatitis B vaccine for use in immunogenicity assays. The limiting dilution required to induce antibodies in 50% of the test animals was determined for the proposed international reference reagent and three other plasma-derived hepatitis B vaccines. The minimum antigenic dose of these preparations varied widely (100-fold range) between laboratories. However, the expression of potencies of vaccines relative to the proposed International Reference Reagent reduced the variation between laboratories to within a 10-fold range. The reference reagent is intended for use in assays of hepatitis B vaccines in mouse (or guinea-pig) immunogenicity studies. For products made by different procedures, clinical trials in humans are necessary to establish a correlation between the immunogenic potency in animals and man.

Drug Stability↗
PubMed1989

Construction of the endoplasmic reticulum.

To study the construction of the ER, we used the microtubule-disrupting drug nocodazole to induce the complete breakdown of ER structure in living cells followed by recovery in drug-free medium, which regenerates the ER network within 15 min. Using the fluorescent dye 3,3'-dihexyloxacarbocyanine iodide to visualize the ER, we have directly observed the network construction process in living cells. In these experiments, the ER network was constructed through an iterative process of extension, branching, and intersection of new ER tubules driven by the ER motility previously described as tubule branching. We have tested the cytoskeletal requirements of this process. We find that newly formed ER tubules are aligned with single microtubules but not actin fibers or vimentin intermediate filaments. Microtubule polymerization preceded the extension of ER tubules and, in experiments with a variety of different drugs, appeared to be a necessary condition for the ER network formation. Furthermore, perturbations of the pattern of microtubule polymerization with microtubule-specific drugs caused exactly correlated perturbations of the pattern of ER construction. Induction of abnormally short, nonintersecting microtubules with 20 microM taxol prevented the ER network formation; ER tubules only extended along the few microtubules contacting the aggregated ER membranes. This requirement for a continuous network of intersecting microtubules indicates that ER network formation takes place through the branching and movement of ER membranes along microtubules. Cytochalasin B had no apparent effect on the construction of the ER network during recovery, despite apparently complete disruption of actin fibers as stained by phalloidin. Blockage of protein synthesis and disorganization of intermediate filaments with cycloheximide pretreatment also failed to perturb ER construction.

Actins↗
PubMed1989

Synthesis of immunogenic, but non-infectious, poliovirus particles in insect cells by a baculovirus expression vector.

A baculovirus expression vector (AcLeon) derived from Autographa californica nuclear polyhedrosis virus (AcNPV) was prepared containing the complete 6.6 kb coding region of the P3/Leon/37 strain of poliovirus type 3 placed under the control of the AcNPV polyhedrin promoter. The recombinant virus was used to infect Spodoptera frugiperda insect cells. As demonstrated by use of the appropriate antibodies, infected insect cells made poliovirus proteins that included the structural proteins VP0, VP1 and VP3. Poliovirus particles were recovered from extracts of the infected cells and demonstrated to be free from detectable levels of RNA and to be non-infectious in tissue culture. After particle purification by CsCl gradient centrifugation and immunization of outbred mice, antibodies to the structural proteins, including neutralizing antibodies, were obtained. Other recombinant baculoviruses, containing the majority of the capsid coding region of P3/Leon/37 (e.g. AcCAP21, nucleotide residues 742 to 3318), made an unprocessed precursor to the poliovirus structural proteins. These data suggested that processing of the poliovirus gene product by the AcLeon construct was catalysed by the poliovirus-encoded proteases. The results demonstrated that antigenic and immunogenic poliovirus proteins and empty particles can be made in insect cells by recombinant baculoviruses.

Animals↗
PubMed1988

Ultrastructural localization and characterization of sensory nerves in the rat kidney.

The ultrastructural localization of sensory nerves in the rat kidney was examined by using the chromaffin reaction to distinguish sympathetic catecholaminergic fibres from sensory fibres. The sensory fibres were further characterized by use of an immunoperoxidase staining method to identify nerves immunoreactive for substance P and for calcitonin-gene-related peptide. Sympathetic fibres were observed in the renal cortex, medulla, and pelvis, but sensory fibres were seen only in the renal pelvis. Immunostaining for substance P labelled 40% of the sensory fibres. Following incubation in calcitonin-gene-related peptide antiserum, 53% of the sensory nerves were positively stained. Simultaneous immunostaining for substance P and calcitonin-gene-related peptide resulted in immunoreactivity in 82% of the sensory fibres, a percentage of axons significantly lower than that expected if the axons containing each peptide had been entirely separate populations. The results indicate that sensory nerves in the rat kidney are located entirely in the renal pelvis. On the basis of their neuropeptide content, there appear to be at least four separate populations of sensory axons present: two large groups containing substance P or calcitonin-gene-related peptide alone and two small groups containing both peptides and containing neither.

Animals↗
PubMed1988

Antigen chimaeras of poliovirus as potential new vaccines.

Polioviruses occur as three distinct serotypes, 1, 2 and 3, and are composed of a single-stranded positive-sense RNA genome of approximately 7,450 nucleotides enclosed in an icosahedral particle of diameter 27 nm. The three-dimensional crystallographic structure of poliovirus type 1 has been determined at 2.9 A resolution, providing a detailed knowledge of the folding and arrangement of the individual virus proteins, VP1-VP4. From this and the characterization of monoclonal antibody-resistant mutants, the amino acids contributing to antigenic sites have been identified and located on the surface of the virus particle. Here we describe the construction and characterization of a poliovirus chimaera having a defined region of type 3 inserted into type 1. This virus has composite antigenicity and the substitute site is immunogenic in small animals and primates. The ability to construct such viruses has implications for the design of improved poliovirus vaccine strains or vaccines against other picornaviruses, such as hepatitis A.

Animals↗
PubMed1988

Isolation and structural analysis of a peptide containing the novel tyrosyl-glucose linkage in glycogenin.

The glucosylation site on glycogenin, the protein primer required for de novo glycogen synthesis, has been identified. The glucose is attached at position C1 in a glycosidic linkage with a unique tyrosine, and the sequence surrounding this residue was found to be: His-Leu-Pro-Phe-Ile-Tyr-Asn-Leu-Ser-Ser-Ile-Ser-Ile-Tyr(Glc)-Ser-Tyr-Leu -Pro- Ala-Phe-Lys. The same tyrosine residue is glycosylated whether glycogenin is isolated as a complex with the catalytic subunit of glycogen synthase, or covalently attached to glycogen. The possibility that insulin and growth factors may enhance glycogen synthesis via stimulation of the priming reaction is discussed.

Amino Acid Sequence↗
PubMed1988

The innervation of the renal cortex in the dog. An ultrastructural study.

Two cytochemical techniques were used at the ultrastructural level to study the distribution of specific axon types to different intrarenal structures in the dog. Using the chromaffin reaction to distinguish catecholaminergic fibres from other axon populations, it was found that the renal cortex of the dog is supplied only by catecholaminergic nerves. Immunostaining for tyrosine hydroxylase (TH) labelled all of the intracortical nerves, and 20% to 25% of these profiles also contained dopa decarboxylase (DDC)-immunoreactivity, indicating they were dopaminergic rather than noradrenergic. Both DDC-positive and DDC-negative axons were seen in close association (approximately 80 nm) with blood vessels and juxtaglomerular cells as well as tubular epithelial cells. The distribution of TH- and DDC-immunoreactive nerves in the renal cortex is compatible with existing functional evidence indicating that both dopaminergic and noradrenergic nerves are involved in the regulation of renal blood flow, tubular reabsorption and renin release.

Animals↗
PubMed1988

Emergency department infraclavicular subclavian vein catheterization in patients with multiple injuries and burns.

We assessed the complications associated with emergency department placement of subclavian vein catheters in trauma and burn patients, reviewing the charts of all of the 441 patients admitted to the burn-trauma unit through the emergency department during 1983. Fifty-two patients (12%) had infraclavicular placement of subclavian catheters while in the emergency department. Sex, age, insertion site, blood pressure at time of insertion, indications for placement, catheters left in place, and complications were recorded. Patients with severe chest trauma or known pneumothorax or hemothorax on the ipsilateral side of line placement were excluded. The eight complications (15%) directly attributable to the procedure itself were one pneumothorax, two hematomas at the site of insertion, one knotted catheter, two misplaced catheters, and two episodes of sepsis, confirming the higher complication rates for emergency subclavian catheter insertion. Two upper extremity, 14 gauge percutaneously placed intravenous catheters are usually sufficient for resuscitation; femoral and cutdown routes offer additional sites for massive resuscitation. Subclavian catheterization is seldom needed in the emergency room. Any intravenous lines inserted in the emergency room should be changed within 24 hours to minimize infection.

Burns↗
PubMed1988

Antigenic variation among 173 strains of type 3 poliovirus isolated in Finland during the 1984 to 1985 outbreak.

Antigenic properties of 128 clinical type 3 poliovirus isolates of the 1984 to 1985 Finland outbreak from 95 persons and 45 strains from sewage water specimens were evaluated using five neutralizing monoclonal antibodies (MAbs) directed against an antigenic site (designated site 1) on VP1 at amino acids 89 to 100. All five MAbs neutralized the type 3 poliovirus strains used in the vaccines, P3/Saukett and P3/Sabin, but none of them neutralized the prototype strain of the outbreak (P3/Finland/23127/84). Forty-six percent of the clinical isolates resembled the prototype strain (class A) while the rest of the isolates were neutralized by one or more of the MAbs (classes B to D). Although an antigenic drift from A to one of the other classes was observed in sequential specimens from several individuals, no clear-cut overall change in the class distribution was found within the 3 months time span of the outbreak. Homogeneous virus populations were isolated from the sewage specimens using a microtitre endpoint dilution method. The last positive sewage specimens which were obtained in January to February 1985 still had a majority of the class A strain. Some of the clinical isolates were also tested using MAbs directed against distinct antigenic sites. These studies showed that strains that gave the same pattern of reactivity with site 1 MAbs could be differentiated using antibodies directed against other sites. Fifteen strains belonging to different antigenic subclasses were subjected to partial RNA sequencing of the genome region coding for antigenic site 1. The antigenic variation was usually, but not always associated with corresponding amino acid substitutions in antigenic site 1. These results indicate that the antigenic sites of type 3 poliovirus vary extensively within a given outbreak and even during replication in a given host. This variation may have both pathogenetic and epidemiological significance.

Amino Acid Sequence↗
PubMed1988

Smooth muscle cells can express cytokeratins of "simple" epithelium. Immunocytochemical and biochemical studies in vitro and in vivo.

Cytokeratins are a set of 19 proteins that together constitute the class of intermediate filament protein expressed by epithelial cells and tumors. Using a panel of 9 different monoclonal anti-cytokeratin antibodies, the authors have performed immunocytochemistry on methanol-fixed, frozen sections and methacarn-fixed, paraffin-embedded tissue of human myometrial specimens. Anomalous cytokeratin expression (ACE) by smooth muscle cells was found in all specimens. Immunoblots of this tissue confirmed the presence of cytokeratin 19, and possibly 8. In addition, immunocytochemical studies demonstrated ACE in human fetal tissues within the intestinal muscularis and the heart, especially in the region of the aortic outflow tract, and in 8 of 19 cases of leiomyosarcoma from adults. Indirect immunofluorescence studies were also performed on cells explanted from myometrial tissue; the overwhelming majority of cells derived from these cultures were smooth muscle cells as verified by expression of muscle actins, and a subpopulation of these cells was found to be cytokeratin-positive. ACE was confirmed in vitro by double labeling experiments demonstrating simultaneous expression of muscle actins and cytokeratins within the same cell. The significance of this smooth muscle cell ACE is unknown, but it may be a phenotypic marker of smooth muscle in a proliferative state. ACE could be a source of confusion in the immunocytochemical analysis of poorly differentiated malignancies if a complete panel of antibodies is not employed.

Cells, Cultured↗
PubMed1987

The effect of strain differences on the assay of rabies virus glycoprotein by single radial immunodiffusion.

Antigenic differences between rabies virus strains used for vaccine manufacture can be demonstrated using monoclonal antibodies. We have shown that these differences are sufficiently large to affect the potency values of vaccines measured in single radial immunodiffusion (SRD) assays if the reference and test vaccines are antigenically heterologous. The production of reagents for use in SRD assays for each strain of rabies virus should be considered.

Animals↗