Biomedical subjects
R A Cox
Publications and source records attributed to R A Cox.
Antigenic heterogeneity of an alkali-soluble, water-soluble cell wall extract of Coccidioides immitis.
The antigenic composition of an alkali-soluble, water-soluble cell wall extract of Coccidioides immitis, designated C-ASWS, was assessed by two-dimensional immunoelectrophoresis against goat antisera to C-ASWS and coccidioidin. The results established that C-ASWS from mycelia or spherule cell walls is heterogeneous in composition, containing two distinct antigenic components. One is present as a polymer that is antigenically identical to a polymeric antigen in coccidioidin, designated antigen 2. The other component detected in C-ASWS presented an unusual precipitin pattern in that a cathodal leg was demonstrable in the absence of an anodal leg. This incomplete precipitinogen was also detected in coccidioidin. In addition to the finding that C-ASWS is antigenically heterogeneous, the results provide evidence that the conformational and/or configurational structure of the C-ASWS antigen 2 (or antigen 2-like polymer) is altered during physicochemical extraction. This conclusion is based upon the finding that the immunoelectrophoretic profile of the C-ASWS polymer differs from that of coccidioidin antigen 2. The C-ASWS polymer is characterized by having a small cathodal precipitin peak connected to a large anodal peak, whereas coccidioidin antigen 2 is characterized by a predominant cathodal peak.
Reactivity of alkali-soluble, water-soluble cell wall antigen of Coccidioides immitis with anti-Coccidioides immunoglobulin M precipitin antibody.
The alkali-soluble, water-soluble cell wall antigen of Coccidioides immitis (C-ASWS) mycelia and spherules was shown to react with anti-Coccidioides immunoglobulin M (IgM) precipitin antibody, both in the classical tube precipitin test and in the immunodiffusion assay for tube precipitin antibody (IDTP). The reactions obtained between C-ASWS and reference IgM precipitin antibody were identical to the reaction obtained when reference coccidioidin (CDN) was used. Definitive proof that C-ASWS extracts contain antigenic determinants that are reactive with IgM tube precipitin antibody was obtained by solid-phase immunoadsorption. Elution of reference IDTP antiserum over a column containing mycelium C-ASWS coupled to Sepharose 4B completely adsorbed precipitin antibody; i.e., reactivity in the IDTP was demonstrable in the column eluate but not in the column effluent fraction. The antigenic composition of C-ASWS extracts was evaluated and compared with that of CDN by two-dimensional immunoelectrophoresis against burro anti-CDN. The results established that both mycelium and spherule C-ASWS contain antigenic determinants in common with only one antigen present in CDN. The latter, designated antigen 2, is a large polymer which is predominant among the antigenic components in CDN. On a dry weight comparison, antigen 2 determinants were most concentrated in spherule C-ASWS, followed by mycelium C-ASWS and reference IDTP antigen. The finding that C-ASWS extracts are reactive with IgM tube precipitin antibody and are antigenically identical to antigen 2 in CDN suggests that antigen 2 is the biologically active component of CDN in tube precipitin assays.
Determination of pyridoxal phosphate levels in the brains of audiogenic and normal mice.
The concentrations of pyridoxal-5'-phosphate in the brains of audiogenic and normal mice were measured fluorimetrically. The brain of the audiogenic mouse (DBA/2J) contains 25% more pyridoxal-5'-phosphate than the brain of a control mouse. Intraperitoneal injection of this substance causes a transient increase of its concentration in the brain, lasting a few hours. The substance thereafter is degraded to pyridoxal and pyridoxic acid.
A method for predicting the location of particles sedimenting in sucrose gradients.
A theory was developed for the calculation of the positions of zones of particles sedimenting through a sucrose gradient. Equations were derived for particles sedimenting through gradients in which the sucrose concentration is (a) a linear function of radius, or (b) a hyperbolic function of radius. Computations were made for both swing-out and zonal rotors. The theory, which is based on direct integration of the sedimentation equation, exploits equations relating (a) the density of sucrose solutions to sucrose concentration and (b) the viscosity of sucrose solutions to sucrose concentration, and also the concept of reduced time (T/2 = S20.w integral of t to w2dt) of Fujita. The required computations may be made using a scientific calculator. Experimental support for the theory was obtained.
Coccidioides immitis vaccine: potential of an alkali-soluble, water-soluble cell wall antigen.
C-ASWS-M, the alkali-soluble, water-soluble cell wall antigen of Coccidioides immitis mycelia, was evaluated for its vaccine potential in mice. Vaccination with 0.5-, 1.5-, or 3-mg doses of C-ASWS-M in complete Freund adjuvant provided a significant level of protection against intraperitoneal challenge with 1,500 arthroconidia (P < 0.0001 with each dose). Vaccination with 1 mg of C-ASWS-M protected mice against intranasal challenge with 50 (P < 0.05) and 500 (P < 0.01) arthroconidia, but not against intranasal challenge with 1,500 arthroconidia (P > 0.05).
Axillary lymphadenitis due to Mycobacterium avium-intracellulare.
A 5-year-old girl presented with a swelling in the right axilla from which Mycobacterium avium-intracellulare was cultured. The gland was excised and she made an uneventful recovery.
The histopathology of rat lung following short term exposures to mixed oxides of nitrogen (NOx).
The histopathology of rat lung after exposure to high concentrations of mixed oxides of nitrogen (NOx) has been studied. Considerable damage was observed, which initially took the form of 'thickening' and 'blebbing' of the alveolar epithelium and disruption of type II pneumocytes. These early changes were attributed to the direct effect of the oxidant action of NOx. There then followed a latent period of approximately 6 h after which the development of oedema of the interstitium and alveolar septum was observed. Clinical observations and the results from light and electron microscopical examination suggested that the lung damage caused by exposure to 518 parts/10(6) NOx for 5 min was greater than that caused by 1435 parts/10(6) for 1 min. This was not supported by the findings from light microscopy where similar damage was observed at both dose levels. These results suggest that such exposures might pose a risk of lung damage to man.
The nucleotide sequence at the 3'-end of Neurospora crassa 18S-rRNA and studies on the interaction with 5S-rRNA.
The sequence of more than 100 nucleotides at the 3'-end of Neurospora crassa 18S-rRNA was determined by chemical sequencing techniques. Extensive homologies with 18S-rRNA from other eukaryotes were found. Inspection of the nucleotide sequence at the 3'-end of N. crassa 5S-rRNA revealed the presence of sequences complementary to a region near the 3'-terminus of 18S-rRNA. Under the appropriate conditions a complex was formed between 18S-rRNA and 5S-rRNA (Tm 53 degrees C). Interaction was detected between 5S-rRNA and a specific 3'-terminal fragment from 18S-rRNA and between 18S-rRNA and a specific 3'-terminal fragment from 5S-rRNA. These findings are consistent with the idea that intermolecular base-pairing between nucleotides at the 3'-ends of 18S-rRNA and 5S-rRNA may be functionally important within the ribosome. Further investigation revealed that this intermolecular base-pairing is not essential for ribosome stability.
Drug resistance among infantile enteropathogenic Escherichia coli strains isolated in the United Kingdom.
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Periodicity in the length of 3'-poly(A) tails from native globin mRNA of rabbit.
Globin mRNA from rabbit reticulocytes was labelled at the 3'-end with [5'-32P]pCp by T4 RNA ligase. The 3'-poly(A) tail was released by digestion of mRNA with T1 ribonuclease and its size distribution determined by gel electrophoresis and autoradiography. The length of the 3'-poly(A) tails varied from about 15-150 residues, but the size distribution exhibited peaks in the abundance of poly(A) species at intervals of approx. 25 residues. This periodicity appears to reflect the manner in which proteins bind to the 3'-poly(A) tail. The function of such regular interactions may be to control mRNA breakdown in the cytoplasm.
Specificity of immunoglobulin E in coccidioidomycosis and correlation with disease involvement.
Serum immunoglobulin E (IgE) antibodies were quantitated in 26 patients with active pulmonary coccidioidomycosis, 59 patients with active disseminated disease, 12 patients in clinical remission, and 91 healthy subjects. Significant differences were obtained in IgE serum levels of patients with active disease versus healthy subjects (P less than 0.0001). Patients with pulmonary coccidioidomycosis did not differ in their IgE levels when compared with patients with disseminated disease. However, serum IgE levels were significantly increased in patients with disease involving two or more organ systems when compared with patients with pulmonary disease or extrapulmonary disease involving a single organ system (P less than 0.02). Total serum IgE correlated with anti-Coccidioides IgE (P less than 0.001), but with only six exceptions, patients with anti-Coccidioides IgE also exhibited IgE antibodies to 1 or more of 12 common allergens. The correlation between hyperproduction of IgE and disease severity coupled with the depressed cell-mediated immune status of patients with this disease suggests a defect(s) in the T-lymphocyte population which functions to regulate IgE synthesis.
Immune complexes in coccidioidomycosis. Correlation with disease involvement.
Circulating immune complexes were quantitated by Clq-binding assays of serum from 73 patients with active coccidioidomycosis, 5 patients with inactive disease, and 34 healthy subjects. Immune complexes were detected in serums of 8 (44%) of 18 patients with active pulmonary disease only and 22 (40%) of 55 patients with active disseminated disease. Results in none of 5 patients with inactive disease and in only 2 (9%) of 34 healthy subjects were positive by the Clq-binding assay. Immune complex levels did not differ in patients with pulmonary disease versus those with disseminated disease. However, immune complexes did correlate with disease involvement. Of 57 patients with coccidioidomycosis involving a single organ system (pulmonary or extrapulmonary), 19 (33%) had immune complexes compared with 6 (67%) of 9 patients with disease involving 2 organ systems, and 5 (71%) of 7 patients with disease of 3 or more organ systems. Immune complex levels correlated with serum IgG, but did not correlate with serum complement-fixing antibody titers to coccidioidin. Rather, the correlation curve between immune complexes and complement-fixing antibody titers yielded a bell-shaped distribution. This distribution pattern suggests that changes in antibody concentration may have effected the size and lattice of immune complexes, resulting in altered detection and/or clearance from the bloodstream.
HLA phenotypes in Mexican Americans with tuberculosis.
HLA-A, -B, and -C phenotype distributions in 100 Mexican Americans with active tuberculosis were compared with HLA phenotypes in 50 healthy, tuberculin-skin-test-positive and 50 healthy, tuberculin-skin-test-negative Mexican Americans. Although there existed differences in the phenotype frequencies of 5 antigens (Aw30, Aw33, B7, B15, and B17) among the 3 study groups, these differences were not significant using p values that were corrected for the number of antigens tested. Thus, susceptibility (or resistance) to tuberculosis in Mexican Americans does not appear to be linked to a specific HLA-A, -B, or -C phenotype.
Structural aspects of eukaryotic ribosomes.
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A study of the arrangement of 18 S rRNA within 40 S subparticles of rabbit ribosomes.
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A study of the accessibility of the 3'-ends of rRNA within mammalian ribosomes.
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Mature 23 SrRNA of prokaryotes appears homologous with the precursor of 25--28 rRNA of eukaryotes: comments on the evolution of 23--28 rRNA.
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