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Biomedical subjects

M A Gordon

Publications and source records attributed to M A Gordon.

At least 73 records · Page 4Linked to original sources
PubMed1985

Interactions of pyrethroids with phosphatidylcholine bilayers: comparisons in liposomal systems exhibiting large or small radii of curvature.

Pyrethroid interactions with dipalmitoyl phosphatidylcholine (DPPC) vesicles have been characterized in bilayers having large and small radii of curvature. The abilities of pyrethroids to alter the gel-fluid phase transition profiles were determined by steady state fluorescence anisotropy and phase-modulation lifetime techniques using the fluorescent probes cis- and trans-parinaric acid. Using the geometric isomers of parinaric acid as membrane probes, pyrethroids were found to lower the phase transition temperature (Tc) of DPPC large multilamellar vesicles with the same order of comparative effectiveness as previously reported using the fluorescent probe 1,6-diphenyl-1,3,5-hexatriene (DPH). Permethrin had a greater depressive effect upon the Tc of DPPC in the small unilamellar vesicle (SUV) system than in the large multilamellar system. Conversely, allethrin was less effective in reducing the Tc of DPPC SUVs. The enhanced effect of permethrin in decreasing the Tc of DPPC SUVs was greatest in regions of more rigid lipid packing, as determined by trans-parinaric acid fluorescence parameters. The results indicate that changes in lipid packing configuration caused by differing bilayer radii of curvature may alter the interactive characteristics of pyrethroids with lipid membranes.

Diphenylhexatriene↗
PubMed1985

An outbreak of histoplasmosis in a prison.

An investigation of three suspected cases of pulmonary histoplasmosis among 600 employees at a New York prison in a nonendemic area resulted in identification of 12 additional previously unrecognized cases. The 15 cases presented with diagnostic findings between February 1978 and October 1981; 10 were in prison employees, three in inmates and two in community persons. Unlike other outbreaks, cases presented over several years with chronic pulmonary lesions in the absence of an episode marked by acute respiratory illnesses. Of the 13 prison-associated cases, seven had undergone diagnostic thoracotomies for chest x-ray abnormalities. A skin test survey of a random sample of employees showed 53% to have positive histoplasmin skin tests compared with 11% in a community control population (chi 2 = 23.4, p less than 0.001). Over 63% of employees on the job for two or more years reacted positively compared with only 13% of those employed less than two years. Testing of some inmates showed 84% with residence of two years or more to be positive, compared with 20% for those with less than two years. A review of potential exposure sources revealed three sites where bird dropping accumulations had been cleared in 1978-1979. Four specimens from two of these areas were positive for Histoplasma capsulatum. The affected sites were treated with a 3% formalin solution and there have been no subsequent cases.

Adult↗
PubMed1985

Corneal transplant infection by Paecilomyces lilacinus.

Paecilomyces lilacinus was cultured from an ulcerated corneal transplant, sections of which, following surgical removal, revealed dense mycelial growth throughout the corneal remnant and penetrating Descemet's membrane. PAS-stained sections showed, in addition to the hyphae, numerous small, ovoid elements consistent with conidia of P. lilacinus. Infection apparently had spread to the transplant from the recipient's cornea. The fungal isolate proved resistant, in vitro, to amphotericin B, 5-fluorocytosine, and pimaricin, but sensitive to ketoconazole and moderately sensitive to miconazole. Following a second transplant and intensive antifungal therapy, the infection appears to have been eliminated.

Aged↗
PubMed1984

Adherence of digested tissue sections for fungal immunofluorescence.

Specific immunofluorescence (IF) staining is helpful and often decisive in diagnosis of deep mycoses by examination of host tissue sections. Brightness of fluorescence may be significantly enhanced by prior digestion of tissues with trypsin, but the treatment tends to separate sections from slides. This is avoided by replacement of albumin in the process by an inexpensive commercial product, Elmer's Glue-All. The entire IF staining procedure for fungi in tissue sections is reviewed here, with emphasis on adhesion and digestion of sections.

Adhesives↗
PubMed1984

Mushroom poisoning. Case reports and a review of therapy.

Four incidents of mushroom poisoning, representing four of the seven established groups of toxic mushrooms, are presented. These case reports illustrate the range of gastrointestinal and neurological symptoms caused by mushroom poisoning and reflect a nationwide increase in reports of serious poisonings in recent years. Severity of poisonings often parallels the time span between consumption and onset of symptoms, with serious poisonings having longer incubation periods. New therapies for amatoxin poisoning may reduce mortality caused by these poisonings.

Acute Kidney Injury↗
PubMed1984

Connective tissue activation. XXVIII. A connective tissue activating peptide from human urine.

A protein factor in human urine which has the ability to activate connective tissue cells has been identified and partially purified; it appears to be different from epidermal growth factor and IgG. This urinary connective tissue activating factor (CTAP-U) is nondialyzable, labile to protease, stable to thiols, heat, and acid, and has an acidic isoelectric point. Purified preparations of CTAP-U have biologic activities that cause human connective tissue cells to synthesize incremental amounts of 14C-hyaluronic acid, 35S-proteoglycans, and 3H-DNA in vitro. The cell spectrum responsive to this substance includes human synovial cells, human chondrocytes, and skin fibroblasts. CTAP-U does not react with antisera to connective tissue activating peptide-III or to antibodies against IgG or its Fc and Fab fragments. Furthermore, CTAP-U does not cross-react in a radioreceptor assay for insulin, basic somatomedin, or epidermal growth factor-urogastrone. Utilizing standardized isolation conditions, CTAP-U preparations with these properties have been isolated from the urine of 6 normal individuals.

Cartilage↗
PubMed1984

Treatment of mobile phase particulate matter in low-angle quasi-elastic light scattering.

The method of quasi-elastic laser light scattering (QLS), particularly at low forward scattering angles, has been complicated by the transient presence of Mie or large Rayleigh scattering particles which contaminate the scattering volume. These large contaminating particles have substantial effects on photon correlation spectroscopy because the presence of these larger scatterers tends to decrease the value of the apparent diffusion coefficient of the particle of interest. A method is presented which yields more accurate diffusion constants by autocorrelation of selected photon count periods representative of minimal Mie or large Rayleigh particle contamination. This method was applied to the determination of the apparent diffusion constant for four proteins-ovalbumin, chymotrypsinogen-A, bovine serum albumin, and ribonuclease-A.

Animals↗
PubMed1984

Correction of anomalous covariance functions in low-angle quasi-elastic light scattering.

The application of low-forward angle quasi-elastic light scattering to characterization of biological systems has been limited by maximal sensitivity of this approach to the transient presence of large Rayleigh or Mie scattering particles which contaminate the scattering volume. These particles result in anomalous autocovariance curves which translate to erroneous estimates of particle diffusion constants and Stokes radii. We have systematically considered two approaches to correct the cause of such anomalies before the autocorrelation step. This work has led to workable methods that allow low-angle quasi-elastic light scattering to provide reliable estimates of particle size. The approaches are useful in correcting errors due not only to 'dust' but also to more rapidly moving scatterers. To illustrate the method, bovine serum albumin and ovalbumin were used as example proteins.

Light↗
PubMed1984

Paecilomyces lilacinus (Thom) Samson, from systemic infection in an armadillo (Dasypus novemcinctus).

Paecilomyces lilacinus was recovered in culture from pulmonary lesions and other internal organs of a captive armadillo. Impression films and smears of the lung tissue revealed numerous budding yeast-like cells, many of them appearing encapsulated and resembling intracellular forms of Histoplasma capsulatum. Yeast-like forms developed in culture on appropriate media at 35 degrees C. The armadillo isolate was compared in culture at both 27 degrees C and 35 degrees C with bamboo rat and human isolates of Penicillium marneffei. The two species were also subjected to serologic and pathogenicity studies. Sensitivities of the armadillo isolate to five antifungal agents in vitro were consistent with those of three human isolates of this species but contrasted sharply with those of P. marneffei.

Animals↗
PubMed1984

Phialophora parasitica, an emerging pathogen.

Monoconidial cultures derived from 12 clinical and environmental isolates of Phialophora parasitica were compared with respect to morphologic and physiologic characteristics and response to antifungal agents. No yeast cells were seen in 1- and 3-week-old slide culture preparations. Also, not all of the distinguishing characteristics of this species were displayed by all isolates on all media examined. Although the isolates grew on Sabouraud agar with chloramphenicol and cycloheximide, some inhibition was observed. All cultures were strongly urease-positive and hydrolyzed casein and starch; most decomposed tyrosine but not gelatin. All but one environmental isolate grew well at both 23 and 37 degrees C, but none grew at 40 degrees C. In the sensitivity testing the isolates did not vary much in their response to each drug, although some anomalies were observed. Amphotericin B and miconazole had minimum inhibitory concentrations in the low sensitivity range (2.0-8.0 and 2.5-10 micrograms m-1 respectively), for most isolates, and most isolates were resistant to both 5-fluorocytosine and ketoconazole. Limited observations were made on three other Phialophora species which might be confused with P. parasitica.

Amphotericin B↗
PubMed1984

Effect of tricyclic antidepressant drugs on lymphocyte membrane structure.

Tricyclic antidepressant-induced perturbations of murine splenic lymphocyte membranes and cell surface concanavalin A receptor mobility have been investigated using the fluorescent probes diphenylhexatriene and fluorescein-conjugated concanavalin A. Results of these studies illustrate the possible relationship between tricyclic antidepressant-induced membrane perturbations and tricyclic antidepressant-induced suppression of the normal murine lymphocyte mitogen response. Tricyclic antidepressant effects on murine splenic lymphocyte membranes are dose-, time- and temperature- dependent. Murine lymphocyte concanavalin A cell surface receptor mobility is not apparently altered by the tricyclic antidepressants.

Animals↗
PubMed1984

Effects of pyrethroids on lymphocyte membrane lipid packing order.

The effects of pyrethroids on the membrane lipid packing order of murine splenic lymphocytes have been investigated by utilizing the fluorescent probe 1,6-diphenyl-1,3,5-hexatriene. Fluorescence anisotropy and lifetime measurements indicated alterations in the environment of the probe at pyrethroid concentrations near 1 microM. Decreased packing order of membrane lipids was detected for permethrin and cypermethrin by decreased anisotropy values. Permethrin and cypermethrin decreased fluorescence lifetime over a concentration range similar to that causing anisotropy changes. Anisotropy was predominantly increased in the presence of fluvalinate and fenpropathrin, indicating pronounced quenching of fluorescence by these compounds. However, the anisotropy changes in response to fluvalinate and fenpropathrin occurred at concentrations which were similar to effective concentrations of permethrin and cypermethrin. Compared to the other pyrethroids tested, allethrin required approximately 10 fold higher concentrations to alter anisotropy and lifetime values. Effects of pyrethroids on the phase transition of dipalmitoyl phosphatidylcholine liposomes were also studied to give further insight into the membrane interactions of these compounds. Results from the liposomal system indicate that the effects of pyrethroids on membrane order which were observed in the lymphocyte may be generalizable to other cell types.

Allethrins↗
PubMed1984

Effects of pyrethroids on lymphocyte mitogenic responsiveness.

The in vitro effects of pyrethroids on the mitogenic responsiveness of murine splenic lymphocytes to concanavalin A (Con A) and lipopolysaccharide (LPS) have been determined. Mitogenic stimulation was measured by uptake of [6-3H]-thymidine. Permethrin and cypermethrin inhibited the mitogenic response to Con A over a concentration range of 1 X 10(-5) M to 5 X 10(-5) M. Relative to these pyrethroids, slightly lower concentrations of fenpropathrin were required to inhibit mitogenic responsiveness to Con A. Fluvalinate was least effective of the pyrethroids tested, and caused mitogenic inhibition at concentrations of 1.5 X 10(-5) M to 5 X 10(-5) M. Unlike the other pyrethroids, concentrations of fluvalinate as high as 1 X 10(-4) M did not result in complete inhibition of the mitogenic response to Con A. Allethrin, was the most potent inhibitor, with effective concentrations in the range of 1 X 10(-6) M to 1.5 X 10(-5) M. Permethrin (3 X 10(-5) M) inhibited the mitogenic response at each of several concentrations of Con A tested, and did not cause a shift in the lymphocyte mitogenic dose-response to Con A. The mitogenic responsiveness to LPS was found to be inhibited by allethrin and permethrin at the same concentrations which inhibited the mitogenesis induced by Con A. The results support the possibility of immune suppression by pyrethroid exposure.

Allethrins↗
PubMed1983

Comparative studies on influenza B virus. I. Biological properties and polypeptide composition of strains isolated in different years.

Influenza B viruses isolated in 1940, 1950 and 1970 belonged to antigenically remote subgroups according to the antigenic composition of haemagglutinin (HA). Antigenically related strains isolated in 1972-1976 differed by their reproduction capability, by their sensitivity to inhibitors in mammalian sera and by affinity to specific antibodies in human sera. Certain correlation between these properties was observed by strains of the Hong Kong variant. Polyacrylamide gel electrophoresis (PAGE) showed that the viruses under study differed in the mobility of the major HA chain (HA1). Molecular weights (MW) of HA1 of antigenically similar influenza B viruses isolated in 1972-1976 revealing different biological properties varied from 52.5 K to 58 K. Neuraminidase (NA) of influenza B/Leningrad/369/75 virus purified by electrophoresis in acetate cellulose consisted of 2 polypeptides with apparent MW of 62 K and 57 K. All viruses examined showed similar mobility of the NA polypeptide MW 57 K; the mobility of the former polypeptide was similar to that of nucleoprotein (NP).

Antiviral Agents↗
PubMed1983

Attenuated influenza B virus recombinants obtained by crossing of B/England/2608/76 virus with a cold-adapted B/Leningrad/14/17/55 strain.

Crossing of an attenuated influenza B virus strain (B/Leningrad/14/17/55) passaged at a low temperature with a virulent influenza B virus strain (B/England/2608/76) yielded recombinants similar in the antigenic specificity of their haemagglutinin (HA) and neuraminidase (NA) to B/England/2608/76 strain, but possessing an RCT37.5 marker alike to the attenuated donor. Analysis of the genome composition of 2 recombinants has shown that they inherited genes coding for P (1, 2, 3) and M (7) proteins from the attenuated parent, but genes coding for HA (4), NA (6), NP (5) and NS (8) proteins from the virulent parent. All recombinants proved to be areactogenic for adult volunteers with no pre-existing antibody to the corresponding HA (less than or equal to 8); however, they had a reduced immunogenicity as compared to parent viruses.

Adult↗
PubMed1983

Search for optimal scheme for administering live allantoic influenza vaccine.

The effect of vaccine dilution and composition on indices of vaccination activity was studied in a live allantoic influenza vaccine administered intranasally to adults. The vaccine was shown to be usable in a 1:1 (instead of 1:5) dilution without risk of its reactogenicity rising. An inhibition of component A(H3N2) was observed in a bivalent vaccine obtained by combining directly before use two monovalent vaccines, A(H1N1) and A(H3N2). The conclusions and recommendations based on the results of the present study have practical implications in influenza control.

Antibodies, Viral↗