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Biomedical subjects

G D Johnson

Publications and source records attributed to G D Johnson.

At least 109 records · Page 6Linked to original sources
PubMed1988

Perilymphatic fistula: a New Hampshire experience.

Thirty-five patients with perilymphatic fistulas (PLFs) are presented. Of this group of 35 patients (39 ears), 4 patients did not have fistulas that could be observed with certainty but were presumed to have fistulas by virtue of their excellent response to surgical repair. Our case reports provide examples of the great variety and possible classifications of presentations and symptom complexes that lead one to suspect the diagnosis of perilymphatic fistula. Comments on diagnostic and therapeutic modalities and on postoperative care and counseling are included. The age range of patients in our series is 3 to 67 years. Four patients are under age 20, and an additional three patients probably developed their symptoms prior to age 20 but presented later. Twenty-three (79%) of 29 patients with spontaneous PLFs began having symptoms closely related to some event involving physical or mechanical stress, and a high percentage (76%) had symptoms aggravated by physical stress. Six are believed to have fistulas of congenital origin. There is a sibling pair and a mother and son in the series; these four people had bilateral fistulas.

Adolescent↗
PubMed1988

Partial characterization of a fibroblast-stimulating factor produced by cloned murine T lymphocytes.

T cells may regulate tissue fibrosis through the elaboration of soluble factors that stimulate fibroblast growth. The authors previously identified a factor produced by cloned Schistosoma mansoni antigen-specific T cells which served as a competence factor for murine fibroblasts. In the present report, they further characterize this fibroblast-stimulating factor (FsF) and differentiate it from a number of other T-cell-derived lymphokine activities. Crude supernatants from concanavalin-activated cloned T cells were fractionated by gel filtration, ion exchange, or reversed-phase high-pressure liquid chromatography. FsF has an apparent molecular weight of 17,000 and could be differentiated from colony-stimulating factor (CSF), interleukin-3 (IL-3), and interferon (IFN) on the basis of chromatographic characteristics. Highly purified or recombinant IL-2, IL-3, CSF, and IFN had no significant effect on fibroblast proliferation. Furthermore, a monoclonal anti-B-cell-stimulating factor-1 antibody only partially blocked the fibroblast proliferation induced by T-cell supernatants.

Animals↗
PubMed1987

The haemolytic uraemic syndrome and anaesthesia.

The Haemolytic Uraemic Syndrome is the most important cause of renal failure in infancy and childhood. The disease usually consists of a typical triad of renal failure, haemolytic anaemia, thrombocytopenia. It is, however, a multisystem disorder which may also involve the liver as well as cardiovascular, pulmonary and central nervous systems. We present a case of a female child with Haemolytic Uraemic Syndrome who presented for placement of an arteriovenous shunt to facilitate haemodialysis. The clinical presentation and management of the Haemolytic Uraemic Syndrome is discussed. Anaesthetic management of patients with the Haemolytic Uraemic Syndrome is discussed and recommendations are made.

Anesthesia, General↗
PubMed1987

Granulocyte/macrophage progenitor cells from peripheral blood and bone marrow differ in their response to prostaglandin E1.

Prostaglandins of the E series (PGE) inhibit proliferation of normal bone marrow granulocyte/macrophage progenitors (CFU-GM). Circulating CFU-GM are known to differ from marrow CFU-GM in many characteristics, and in the present study, we compared the effect of PGE1 on circulating and bone marrow progenitors in normals and in patients with chronic myelogenous leukemia (CML). PGE1 caused a dose-dependent inhibition of normal marrow CFU-GM. Circulating CFU-GM were inhibited only at concentrations of 10(-5) mol/L or greater, and progenitor proliferation was, in fact, significantly stimulated at PGE1 concentrations between 10(-8) and 10(-6) mol/L. Bone marrow CFU-GM from patients with CML were inhibited in a manner similar to that of normal bone marrow. Circulating cells from patients with CML were, however, less sensitive to PGE1 inhibition than CML bone marrow cells and demonstrated a pattern intermediate between normal circulating and normal marrow progenitors. These studies suggest that peripheral blood and bone marrow contain different progenitor cell populations.

Alprostadil↗
PubMed1986

The IgA subclass responses of human lymphocytes to B-cell activators.

The induction of IgA synthesis in normal peripheral blood lymphocytes cultured in the presence of 5 different B-cell activators was studied by immunofluorescence using monoclonal antibodies to the two subclasses. The surface phenotype of normal cells after overnight culture in the absence of mitogen showed a mean ratio IgA1:IgA2 of 2.7:1; cells with cytoplasmic IgA were very rare. Results obtained on different donors after stimulation showed considerable variation; IgA1 was the predominant subclass in Epstein-Barr virus-stimulated cultures, whereas pokeweed mitogen induced a predominantly IgA2 response; cells stimulated with Staphylococcus aureus, Branhamella catarrhalis and lipopolysaccharide and unstimulated cells showed a 1:1 ratio of the subclasses. It is concluded that in this system IgA subclass expression is a function of the activator employed.

Antigens, Surface↗
PubMed1986

Expression of a 215,000-dalton nuclear envelope protein decreases during cell maturation.

The monoclonal antibody AGF2.3 identifies a nuclear envelope protein expressed at high levels in most transformed cell lines and weakly expressed in or absent from normal tissues and primary cell cultures. Here we report that expression of AGF2.3 antigen relates to the maturation status of cells. When HL60 cells were induced to mature loss of AGF2.3 antigen correlated with the appearance of neutrophils in culture. Acute myeloid leukaemia cells were intensely labelled by AGF2.3 antibody whereas chronic myeloid leukaemia cells were weakly reactive. Staining of tonsil epithelium showed a progressive loss of antigen during epithelial cell maturation. High levels of AGF2.3 antigen in most permanent cell lines suggest that such lines represent transformation of immature cells.

Antibodies, Monoclonal↗
PubMed1986

Use of monoclonal antibodies reactive with secretory epithelial cells for the immunocytochemical identification of plasma cells.

Six monoclonal antibodies (McAbs) were identified as plasma cell-reactive when screened on sections of human tonsil. They were all produced following immunisation of mice with cells of a human plasmacytoid line. Three of the antibodies also stained the cytoplasm (but not the surface) of blood B cells and were unreactive with other leucocytes; one McAb showed broad lymphocyte reactivity and two were completely unreactive with blood leucocytes; on testing with a panel of cell lines specificity for the plasmacytoid line was demonstrated by three of the McAbs. In spite of the marked restriction shown by the reactivity of these antibodies in tests on cells of haemopoietic origin, tests on other human tissues - including thyroid and pancreas - showed that a related antigen was present in the cytoplasm of secretory epithelial cells. The overall patterns of reactivity of the individual McAbs on various tissues and blood lymphocytes were different. Comparisons were made with the established McAb OKT10, which binds to plasma cells, early stem cells and activated lymphocytes; its binding to plasma cells was confirmed and it was shown that it did not stain secretory epithelia. The potent reactions obtained with the new McAbs suggest that antibodies to antigens associated with epithelial cell secretory apparatus provide potentially useful reagents for studying plasma cells.

Animals↗
PubMed1986

Arterial isoflurane concentration and EEG burst suppression during cardiopulmonary bypass.

Isoflurane (1.5 to 3.0 vol% in oxygen) was used to control intraoperative hypertension in 10 patients undergoing hypothermic cardiopulmonary bypass surgery. Isoflurane was administered through the membrane oxygenator of the bypass pump and yielded plateau concentrations in arterial blood ranging from 36.6 to 84.4 micrograms/ml (0.5 and 1.16 vol%, respectively). Isoflurane dosing resulted in prolonged periods (21 to 63 minutes) of EEG burst suppression and isoelectric activity in nine patients. Burst suppression was not a result of hypothermia. There was a close temporal relationship between isoflurane concentration and the onset of burst suppression (mean onset time: 27.3 +/- 4.56 minutes after isoflurane begun). The mean arterial isoflurane concentration at the onset of burst suppression was 46.5 +/- 10.7 micrograms/ml; the nasopharyngeal temperature was 26.0 degrees +/- 0.61 degrees C. Isoflurane was eliminated rapidly from blood with a mean apparent t1/2 of 18.8 +/- 5.46 minutes.

Adult↗
PubMed1986

An improved high pressure liquid chromatographic method for the determination of isocyanates using "nitro reagent".

The chromatographic problems associated with the excess derivatizing reagent, N-4-nitrobenzyl-N-n-propylamine, in the commonly used HPLC method for the determination of isocyanates have been eliminated. An aqueous extraction removed the excess reagent without affecting the concentration of the urea derivatives. The combination of the extraction with the use of a fast-LC column allowed separation and quantitation of 4,4'-diphenylmethane diisocyanate, 2,4- and 2,6-toluene diisocyanate and hexamethylene diisocyanate within four minutes under isocratic conditions. Detection limits ranged from 2 to 5 ng injected.

Air Pollutants, Occupational↗
PubMed1986

The epidermal Langerhans' cell population in psoriasis during topical coal tar therapy.

We have studied the effect on the Langerhans' cell (LC) population of topical 3% coal tar therapy. Biopsies were taken from psoriatic plaques and from controls with no skin disease before and after the application of 3% coal tar for one week; LC were identified by immunofluorescence using monoclonal antibody. LC counts expressed per unit epidermal surface length were similar in untreated psoriasis plaques and in normal skin. Differences in the LC population in paired biopsies from both patients and controls showed considerable variation following coal tar treatment but no consistent effect could be demonstrated.

Antibodies, Monoclonal↗
PubMed1986

An antigenic study of human plasma cells in normal tissue and in myeloma: identification of a novel plasma cell associated antigen.

A mouse monoclonal antibody named BU11 which detects an antigen strongly expressed on human plasma cells is described. The antibody stains plasma cells in tonsil sections, fresh and cultured plasmacytoid cells from the bone marrow of patients with multiple myeloma and cells of the plasmacytoid cell line RPMI 8226 used as the immunogen. In vitro studies of pokeweed mitogen (PWM) stimulated peripheral blood B cells and Epstein-Barr virus (EBV) stimulated tonsil B cells show that the antigen is present mainly on cells coexpressing the OKT10 antigen and containing cytoplasmic immunoglobulin (cIg). The BU11 antigen is expressed weakly on some normal B cells and is not present on T cells, monocytes or granulocytes. The antigen is of molecular weight 58kD under reducing conditions and is biochemically distinct from previously described plasma cell antigens.

Animals↗
PubMed1986

Human follicular dendritic cells (FDC): a study with monoclonal antibodies (MoAb).

A collection of new and established FDC-reactive MoAb has been used in an immunohistological study designed to throw light on (a) the nature of FDC (which are of unknown lineage) as judged by their sharing of antigens with other cell types and (b) the reason for the strong expression of some B cell antigens on FDC. The MoAb were tested on: (1) sections of tonsil, (2) sections of lymph nodes from four cases of non-Hodgkin's lymphoma, (3) peripheral blood cells and (4) cells of cultured haemopoietic cell lines. Only one of the ten new MoAb bound to FDC and no other component of the tissues screened. It resembled R4/23, a MoAb known to be specific for FDC. The other nine antibodies showed a range of cross-reactivity patterns involving one or more of the following: monocytes, macrophages, platelets, epithelium, endothelium and connective tissue fibres. Some of the MoAb reacted with B lymphocytes and cells of B lymphoblastoid lines but none showed the restricted FDC-staining pattern associated with MoAb which detect the CD23, P45 antigen. The findings are discussed in terms of the intrinsic or extrinsic nature of the antigens detected.

Antibodies, Monoclonal↗
PubMed1985

Ultrastructure of corpora allata of known activity during the vitellogenic cycle in the cockroach Diploptera punctata.

Ultrastructure was correlated with rates of juvenile hormone synthesis in corpora allata from females of the viviparous cockroach Diploptera punctata at seven daily intervals during the first vitellogenic cycle. Synthetic activity of the glands was determined by in vitro radiochemical assay before the glands were fixed for electron microscopic analysis. The cycle in rates of juvenile hormone synthesis progressed from about 20 pmol h-1 per gland pair (oocytes 0.60 mm long) to a maximum mean rate of 140 pmol h-1 per pair (oocytes 1.40-1.47 mm long) and declined to about 20 pmol h-1 per pair at ovulation (oocytes about 1.65 mm long). Conspicuous ultrastructural changes occurred with changing synthetic rates. In glands with increasing rates of synthesis, mitochondria showed less electron-dense matrix, greater diameter and more irregular shape. Smooth endoplasmic reticulum changed from easily seen to obscure tubules, networks, and vesicles. Rough endoplasmic reticulum appeared in longer, more curved segments. Newly formed autophagic vacuoles appeared in all glands of highest activity rates. In glands with decreasing rates of synthesis, the mitochondrial matrix became denser, width smaller, and shapes less irregular. Smooth endoplasmic reticulum again appeared tubular and distinct. Golgi complexes were more conspicuous. Rough endoplasmic reticulum in whorls and large numbers of autophagic vacuoles continued to be present.

Animals↗
PubMed1985

The nucleotide sequence of tyrosine tRNAQ* psi A from bovine liver.

The nucleotide sequence of tyrosine tRNAQ* psi A from bovine liver was determined to be pC-C-U-U-C-m2G-A-U-A-m2G-C-U-C-A-G-D-D-G-G-acp3U-A-G-A -G-C-m22G-m22G -A-G-G-A-C-U-Q*-psi-A-m1G-A-psi m-C-C-U-U-A-G-m7G-D-m5C-G-C-U-G-G-T-psi-C-G-m1A -U-U-C-C-G-G-C-U-C-G-A-A-G-G-A-C-C-AOH. This tyrosine tRNA is 76 nucleotides in length, and contains two hypermodified nucleosides--3 -3(3-amino-3-carboxylpropyl)uridine (acp3U) and beta-D-galactosylqueuosine (Q*). The molecule also has a pseudouridine in the middle position of the anticodon, and is the first tRNA sequenced which has an adjacent pair of N2,N2-dimethylguanosine (m22G) residues.

Animals↗
PubMed1985

A monoclonal antibody identifies a 215 000-dalton nuclear envelope protein restricted to certain cell types.

The monoclonal antibody, AGF2.3, was isolated from mice immunised with the human promyeloid cell line HL60. By immunofluorescence and immunoelectron microscopy the antibody was shown to bind to the nuclear envelope in uninduced HL60 cells. Immunofluorescent staining was reduced to very low levels in HL60 cells induced to mature to monocytes or neutrophils by addition of 12-0-tetradecanoylphorbol-13-acetate or dimethyl sulfoxide respectively. Blood neutrophils did not express the antigen. Weak immunofluorescent staining of cell nuclei was observed in peripheral blood lymphocytes and in sections of normal human kidney, tonsil and skin epithelium. The AGF2.3 antigen was strongly expressed on the nuclei of 21/21 haemopoietic cell lines and 21/25 permanent non-haemopoietic cell lines representing various cell types. In contrast, the antigen was not expressed by any of six primary (untransformed) cell cultures. These included fibroblasts, endothelial cells and keratinocytes. The antigen was expressed in the Q10 SV-40 transformed cell line derived from a non-expressing primary fibroblast culture. AGF2.3 antibody precipitated a protein with an apparent subunit molecular weight of approximately 215 kDa from Triton X-100 extracts of HL60 and HeLa cells labelled with 35S-methionine. This protein was not detectable in extracts of primary skin fibroblasts prepared in parallel. We conclude that AGF2.3 antibody recognises a previously undescribed protein associated with the nuclear envelope which is expressed at high levels in most transformed cell lines but which is weakly expressed or absent in normal tissues and primary cell cultures.

Animals↗