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Biomedical subjects

J Bailey

Publications and source records attributed to J Bailey.

At least 163 records · Page 9Linked to original sources
PubMed1990

Cellular events during sexual development from amoeba to plasmodium in the slime mould Physarum polycephalum.

Time-lapse cinematography and immunofluorescence microscopy were used to study cellular events during amoebal fusions and sexual plasmodium development in Physarum polycephalum. Amoebal fusions occurred frequently in mixtures of strains heteroallelic or homoallelic for the mating-type locus matA, but plasmodia developed only in the matA-heteroallelic cultures. These observations confirmed that matA controls development of fusion cells rather than cell fusion. Analysis of cell pedigrees showed that, in both types of culture, amoebae fused at any stage of the cell cycle except mitosis. In matA-heteroallelic fusion cells, nuclear fusion occurred in interphase about 2 h after cell fusion; interphase nuclear fusion did not occur in matA-homoallelic fusion cells. The diploid zygote, formed by nuclear fusion in matA-heteroallelic fusion cells, entered an extended period of cell growth which ended in the formation of a binucleate plasmodium by mitosis without cytokinesis. In contrast, no extension to the cell cycle was observed in matA-homoallelic fusion cells and mitosis was always accompanied by cytokinesis. In matA-homoallelic cultures, many of the binucleate fusion cells split apart without mitosis, regenerating pairs of uninucleate amoebae; in the remaining fusion cells, the nuclei entered mitosis synchronously and spindle fusion sometimes occurred, giving rise to a variety of products. Immunofluorescence microscopy showed that matA-heteroallelic fusion cells possessed two amoebal microtubule organizing centres, and that most zygotes possessed only one; amoebal microtubule organization was lost gradually over several cell cycles. In matA-homoallelic cultures, all the cells retained amoebal microtubule organization.

Animals↗
PubMed1990

Changes in pulmonary microvascular permeability accompanying re-expansion oedema: evidence from dual isotope scintigraphy.

The pathophysiological mechanism of pulmonary oedema following rapid re-expansion of a collapsed lung is poorly understood. It has been suggested that the period of collapse or subsequent reinflation produces an increase in pulmonary microvascular permeability. To investigate this, the pulmonary accumulation of the plasma protein transferrin was measured by radiolabelling it in vivo with indium-113m. Plasma protein accumulation was calculated after correcting the accumulation of transferrin for changes in intrathoracic blood distribution by simultaneously monitoring technetium-99m labelled red blood cells. Functional images of plasma protein accumulation were constructed for the lung fields on a pixel by pixel basis. Investigations were performed on 14 subjects after drainage of a pleural effusion (n = 9) or evacuation of a pneumothorax (n = 5), and on 11 control subjects. Plasma protein accumulation was greater over the regions of lung re-expansion (-0.1-9.6, mean 2.9 x 10(-3)/min) than over the corresponding region of the contralateral lung (-1.2-0.8, mean 0.01 x 10(-3)/min; p less than 0.001). Patients who had undergone re-expansion procedures also had significantly greater plasma protein accumulation than normal controls. Nine of the 14 patients in the re-expansion group had clearly identifiable areas of increased plasma protein accumulation that corresponded to the part of the lung that had been re-expanded; no regional abnormalities were recorded in the control group. These results suggest that the reinflated lung displays abnormal microvascular permeability.

Adult↗
PubMed1989

Regional lung microvascular permeability using dual isotope scintigraphy.

We have extended the dual isotope probe technique of Basran et al. for the measurement of pulmonary microvascular permeability (PMVP) to include gamma camera data acquisition and functional imaging of the plasma protein accumulation index (PPA) throughout the lung fields. The study group consisted of 11 patients with possible increased PMVP following the drainage of a pleural effusion or the evacuation of air from a pneumothorax, and 11 control patients. The PPA was calculated (1) for probe data, (2) on a pixel by pixel basis for the camera data, the results being stored in a functional image and (3) for four pixel x four pixel regions of interest positioned over the lung fields using the functional image and raw data as a guide. Functional images of the control group showed uniformly low PPAs throughout the lung fields. Nine of the eleven patients in the effusion/pneumothorax group showed discrete areas of increased PPA on the functional images. In the effusion/pneumothorax group, the re-expanded lung four pixel x four pixel ROI PPA values were significantly higher than the nonexpanded lung ROI values (p less than 0.001). The re-expanded lung ROI values were also significantly higher than the mean of the left and right lung ROIs in the control group (p less than 0.01). Five of the eleven patients in the effusion/pneumothorax group had probe PPAs that differed significantly from zero. We believe that probe positioning problems in the absence of sufficient clinical guidelines were largely responsible for there being no overall significant difference in the probe PPAs between the two study groups.

Adult↗
PubMed1988

Contacts of chick fibroblasts on glass: results and limitations of quantitative interferometry.

We have examined the contacts made by explanted chick heart and limb bud fibroblasts after 24-48 h on glass, using quantitative interference reflection microscopy (IRM). Contacts beneath very thin cytoplasmic lamellae were avoided because the images of such contacts depend on the thickness of the lamellae. Plaque-like focal contacts, distinguished on the basis of shape and low irradiance (darkness), are intimate adhesions to the substratum. These images can be interpreted if it is assumed that microfilaments associated with the lower membrane increase the local cytoplasmic refractive index. The range of irradiances measured for focal contacts was found to be rather wide, and our modelling shows that the most likely explanation for this is that the images receive variable contributions from the adjacent cytoskeleton. For this reason it is particularly difficult to assign a characteristic thickness for these contacts from IRM data. Close contacts, seen principally as 'grey' regions under migrating cells at the edges of the explants, also show a wide range of irradiances. Unlike focal contacts, it is not necessary to postulate any involvement of the cytoskeleton in their images and they can be modelled as regions where an aqueous glycocalyx zone about 20-30 nm thick separates the membrane bilayer from the glass. Paler grey regions that also look like close contacts are apparently formed where the cell surface has lifted several tens of nanometres from the glass.

Animals↗
PubMed1988

Contact-mediated triggering of lamella formation by Dictyostelium amoebae on solid surfaces.

Amoebae of the slime mould Dictyostelium discoideum form broad ultrathin cytoplasmic lamellae by a centripetal contractile process soon after they have spread on certain solid surfaces. We have investigated the surface requirements for initial triggering of this contact-mediated signalling system. The lamellar response is not normally evoked by glass, but is seen on glass covalently derivatized with paraffinic chains, as well as on glass covalently derivatized with amine groups and on glass bearing adsorbed polylysine. We have recorded the frequency of the lamellar response on these surfaces as a function of ionic strength and pH, and have measured the electrostatic potentials of the surfaces by the streaming potential method. Using these data we have concluded that the general trigger for the lamellar response is not a 'simple' physical or chemical property of the substrata: it is not dependent on specific chemical groups, degree of hydrophobicity, electrostatic potential, or charge density, taken as isolated factors. It seems likely that triggering is dependent on the overall energetics of cell-substratum interaction.

Cell Adhesion↗
PubMed1988

Hashimoto's disease in Turner's syndrome.

Sera from 52 patients with Turner's syndrome were analyzed for thyroxine and TSH concentrations, resin T3 uptake, and thyroid antibodies. Thyroid antibody titers were compared to those previously obtained in 53 women with long-standing infertility. Thyroid microsomal and/or thyroglobulin antibody titers were elevated to a level diagnostic of Hashimoto's disease (greater than 1:400) in 25 (48%) patients with Turner's syndrome. Microsomal antibody levels only were elevated in five (9%) patients with infertility. The mean microsomal antibody titers in the patients with Turner's syndrome (1:25, 167 +/- 31,531) were significantly higher than in the infertile patients (1:2560 +/- 2149). The incidence of Hashimoto's disease did not differ significantly among the various karyotypes. The entire clinical spectrum of Hashimoto's thyroiditis was present in Turner's syndrome. Three patients had overt hypothyroidism necessitating L-thyroxine, four had compensated hypothyroidism (serum TSH concentration greater than 10 microU/L and normal serum thyroxine concentrations), while the remaining 18 had normal thyroid function. No relationship was demonstrated between Hashimoto's disease or family history of thyroid disease and karyotype.

Adolescent↗
PubMed1987

Watermelon and ragweed share allergens.

A biotin-avidin amplified ELISA was used to measure antigen-specific IgE for ragweed, representative members of the gourd family (watermelon, cantaloupe, honeydew melon, zucchini, and cucumber), and banana in the sera of 192 allergic patients, each with an IgE greater than or equal to 180 microns/ml. Sixty-three percent (120/192) of the sera contained antiragweed IgE, and of these patients, 28% to 50% contained IgE specific for any single gourd family member. In contrast, no greater than 11% of the sera positive for a given gourd or banana were negative for ragweed. Correlations between ragweed and gourd-specific IgE levels were significant (p less than 0.001), and correlation coefficients between any two gourds exceeded 0.79. In an ELISA system, the extracts of watermelon and ragweed inhibited each other in a dose-dependent manner; the resulting nonparallel inhibition curves indicate that some, but not all, of the allergens in the two extracts are cross-reactive. Isoelectric focusing of watermelon and ragweed extracts in narrow range gel (pH 4 to 6) followed by immunoblotting demonstrated six watermelon allergen bands with isoelectric points identical to those of ragweed allergens. Several remaining bands in the two extracts had differing isoelectric points, however. Six of 26 patients interviewed with watermelon-specific IgE reported developing oropharyngeal symptoms (itching and/or swelling of the lips, tongue, or throat) after ingesting at least one of the study foods, whereas only one of 25 patients interviewed without detectable watermelon-specific IgE reported similar symptoms (p = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Comparison of MAST with radioallergosorbent and skin tests for diagnosis of allergy in children.

The multiple allergosorbent test system (MAST) is a method for measuring total and allergen-specific IgE levels, using autoradiography and densitometry. The purpose of this study was to compare the results of MAST tests with those of radioallergosorbent (RAST) and skin tests as an adjunct to the diagnosis of allergy in children. Twenty children, aged 4 to 19 years, were studied. Total serum IgE level measured by the paper radioimmunosorbent test (PRIST) method ranged from 7 to 1,333 units/mL (geometric mean, 155 units/mL). Total serum IgE level by MAST significantly correlated with the PRIST IgE level. Quantities of allergen-specific IgE measured by MAST and RAST were also significantly correlated. When the diagnostic levels by MAST and RAST were compared with skin test reactions for ragweed, grass, house dust, and mite, MAST had a sensitivity of 59%, a specificity of 97%, and an efficiency of 72%, compared with 67%, 97%, and 78%, respectively, for the RAST analysis. We conclude that MAST and RAST are similar in their ability to measure allergen-specific IgE level, but that neither method is as sensitive as skin tests for detection of allergen-specific IgE.

Adolescent↗
PubMed1986

Evaluation of the cause of nasal and ocular symptoms associated with lawn mowing.

A number of individuals with perennial or seasonal rhinoconjunctivitis state that their symptoms may suddenly worsen on exposure to lawn mowing. Many allergists have believed that this was related to the agitation of molds deposited on the grass. We studied 50 consecutive new patients with rhinitis using history, skin testing, total and specific IgE assays, and nasal smears. Twenty-five patients gave histories of minimal or no change in their nasal symptoms with exposure to lawn mowing, whereas 11 patients had definite, but mild, symptoms, and 14 patients had severe symptoms. Positive skin tests to grasses, trees, and weed pollens were more frequent in those patients with symptoms exacerbated by lawn mowing (p less than 0.03). Symptomatic patients also had higher serum concentrations of total IgE (p less than 0.008) and grass-pollen specific IgE (p = 0.0004). The frequencies of positive skin tests to ragweed pollens, house dust, molds, and grass leaves, as well as the percentage of nasal eosinophils, were not different in the symptomatic and asymptomatic groups. No significant association was found between symptoms and IgE antibodies to molds or grass-leaf extract. We believe that the increased nasal and ocular symptoms coincident with lawn mowing are allergic phenomena significantly associated with skin test sensitivity and specific IgE antibodies to grass pollens but not with sensitivity or specific IgE to molds or grass-leaf extract.

Adolescent↗