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Biomedical subjects

J R Carlson

Publications and source records attributed to J R Carlson.

At least 109 records · Page 6Linked to original sources
PubMed1986

Response of Peyer's patch lymphocyte subsets to Giardia muris infection in BALB/c mice. I. T-cell subsets.

Initial cellular events in the intestinal immune response occur within Peyer's patches and are subject to complex regulation by T cells. The aim of this study was to analyze the response of murine Peyer's patch T, T-helper (Th), and T-suppressor (Ts) cells to Giardia muris infection. Immunocompetent BALB/c mice were infected with G. muris cysts and, at serial times during the infection, Peyer's patch leukocyte suspensions were incubated with fluorescent monoclonal antibodies that identified murine leukocytes, T, Th, or Ts lymphocytes. These suspensions were examined by flow cytometry to quantify each T-cell subset as a percentage of total leukocytes. Total Peyer's patch leukocytes more than doubled in number during the course of G. muris infection and returned to control levels as the infection was cleared. The percentages of Peyer's patch Th and Ts lymphocytes were 34.1 +/- 0.8% (mean +/- SEM) and 6.2 +/- 0.3%, respectively, in the absence of infection, and did not change significantly during Giardia infection. The Th/Ts ratio in Peyer's patches was 5.6 +/- 0.2 in uninfected BALB/c mice and also did not change significantly during clearance of G. muris. We conclude that Peyer's patch leukocytes double in number in response to G. muris infection in immunocompetent mice, G. muris infection does not lead to altered percentages of Peyer's patch T, Th, or Ts lymphocytes, and clearance of G. muris infection is associated with a Peyer's patch Th/Ts ratio of greater than 5.

Animals↗
PubMed1986

Response of Peyer's patch lymphocyte subsets to Giardia muris infection in BALB/c mice. II. B-cell subsets: enteric antigen exposure is associated with immunoglobulin isotype switching by Peyer's patch B cells.

The aim of this study was to quantify the response of Peyer's patch B cells, surface IgA-bearing (sIgA) B cells, and surface IgM-bearing (sIgM) B cells to Giardia muris infection. Following infection of a cohort of immunocompetent BALB/c mice with G. muris cysts, Peyer's patch cell suspensions were prepared at serial time points during the infection, incubated with fluorescein-conjugated monoclonal antibodies directed against murine leukocytes, B cells, sIgA B cells, sIgM B cells, or T cells, and analyzed by flow cytometry. Of total Peyer's patch leukocytes, the percentages of B cells, sIgA B cells, and sIgM B cells in uninfected BALB/c mice were 64.7 +/- 2.0% (mean +/- SEM), 30.3 +/- 1.5%, and 52.5 +/- 2.4%, respectively. The total number of Peyer's patch leukocytes increased significantly (1.8 X) during G. muris infection, and returned to control levels as the infection was cleared. The percentages of Peyer's patch T and total B cells did not change significantly during Giardia infection. However, sequential changes were observed in the percentages and numbers of sIgM and sIgA B cells during the infection. Peyer's patch sIgM B cells rapidly increased in percentage and number, reaching maximum levels 1 week after cyst inoculation. After remaining constant the first week, the number of Peyer's patch sIgA B cells increased during the second week of G. muris infection, reaching a maximum level 11-14 days after cyst inoculation. The data support the hypothesis that immunoglobulin isotype switching in Peyer's patches is induced by antigen exposure.

Animals↗
PubMed1986

Evaluation of three commercial screening tests for AIDS virus antibodies.

Three commercial enzyme-linked immunosorbent assays (ELISA) for acquired immune deficiency syndrome (AIDS) virus antibodies were evaluated using serum that had been characterized by an ELISA and western blot procedure developed at the University of California at Davis (UCD). Each of the commercial tests was more specific than the UCD ELISA, but the UCD ELISA was more sensitive in the detection of sera that lacked reactivity by western blot to the envelope glycoprotein (gp-41). The HTLV-III Bio-EnzaBead (Litton Bionetics, Charleston, SC) was less sensitive and specific than the Abbott HTLV-III EIA (Abbott Laboratories, North Chicago, IL) or the Virgo HTLV-III ELISA (Electro-Nucleonics Inc., Columbia, MD). Overall, 22.9% (57 of 250) and 51.0% of sera that were repeatedly (X2) positive by commercial screening kits tested at blood donor centers and clinical laboratories, respectively, were confirmed by western blot. These results indicate that the screening assays for AIDS virus antibodies are not equal in performance and that positive screening test results must be confirmed by a more specific test like western blot before results are released.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Detection and differentiation by sandwich enzyme-linked immunosorbent assay of human T-cell lymphotropic virus type III/lymphadenopathy-associated virus- and acquired immunodeficiency syndrome-associated retroviruslike clinical isolates.

Monoclonal antibodies can be used in sandwich enzyme-linked immunosorbent assays to measure viral antigens. Such an assay was developed to detect the core protein, p24, of human T-cell lymphotropic virus type III and lymphadenopathy-associated virus, etiologic agents of the acquired immunodeficiency syndrome (AIDS). Another AIDS-associated virus, AIDS-associated retrovirus type 2 (ARV-2) could not be detected in this assay because of the low affinity of one of the monoclonal antibodies to ARV-2 p24. Detection of ARV-2 was accomplished with a monoclonal antibody-rabbit polyclonal antibody sandwich enzyme-linked immunosorbent assay. These two assays were used to efficiently detect AIDS-related viruses in lymphocyte cell cultures and to distinguish strains of the viruses.

AIDS-Related Complex↗
PubMed1986

Evaluation of the indirect immunofluorescence assay as a confirmatory test for detecting antibodies to the human immunodeficiency virus.

One hundred and eighty-four serum specimens were assayed for antibodies to the human immunodeficiency virus. All specimens were screened with a commercial enzyme immunoassay and confirmed by two indirect immunofluorescence assays. Sera were also assayed by Western blot. Results from sera of 48 healthy heterosexual volunteers were all negative by EIA, IFA, and Western blot. Sera from 50 healthy homosexual men negative by EIA were also negative by IFA and Western blot. Sixty-two patients with persistent generalized lymphadenopathy or newly diagnosed AIDS all were positive by EIA, IFA, and Western blot. Of 24 sera from patients with autoantibodies, with no evidence of AIDS-related diseases, five appeared to be false-positive by EIA, since they were nonreactive by IFA and Western blot. In addition, three other samples contained both autoantibodies and human immunodeficiency virus antibodies. False-positive results were observed in both the EIA and IFA with monoclonal antibodies directed toward the MHC class II antigens DQ and DR. The reactivity of these antibodies could not be distinguished from positive patients' sera, in either EIA or IFA. We conclude that in general indirect immunofluorescence performed well as a confirmatory test after screening by enzyme immunoassay for human immunodeficiency virus antibodies.

Antibodies, Viral↗
PubMed1986

Uterine responses to three techniques of breast stimulation.

Uterine contractions produced by three methods of breast stimulation and a placebo were compared in 202 high-risk women between 35 and 44 weeks' gestation during contraction stress tests. Manual stimulation produced significantly more successful responses of three or more contractions within ten minutes than did a heating pad or a placebo, but did not show significant differences when compared with a breast pump. The placebo group showed an increase in contractions over a resting state. Of the women with successful contraction stress tests, over 50% demonstrated exaggerated uterine activity (a hypertonic contraction of greater than 90 seconds, or five or more contractions in a ten-minute period).

Adolescent↗
PubMed1985

AIDS serology testing in low- and high-risk groups.

The performance characteristics of the acquired immunodeficiency syndrome (AIDS)-retrovirus serological tests including enzyme-linked immunosorbent assay (ELISA), Western blot, and immunofluorescence assay were defined in a clinical laboratory setting by testing 1,257 serum specimens from low- and high-risk groups for AIDS. The three prototype AIDS retroviruses (lymphadenopathy-associated virus, human T-lymphotropic virus III, and AIDS-associated retrovirus) were equally suitable as target antigen for these assays. Sera from six of 74 laboratory and health care personnel and 91 of 1,014 unselected blood donors were falsely positive by ELISA (positive to negative ratio [P/N], greater than or equal to 2) based on the lack of Western blot confirmation. Only two true-positives (two [0.2%] of 1,014 blood donors) were detected in these low-risk groups. In contrast, 106 of 108 specimens with ELISA P/N ratios of 2 or greater from the high-risk groups including asymptomatic homosexual men, hemophiliacs, AIDS-related complex patients, and AIDS patients were positive by Western blot and immunofluorescence assay. Four false-negative ELISA results based on positive immunofluorescence assay and Western blot were found in the AIDS patient group. Ten of 69 AIDS patients were negative by all three serological tests. The consequence of maintaining high sensitivity for the ELISA (P/N ratio, greater than or equal to 2) as a screening test was a loss of specificity. The number of false-positive results necessitated the use of a confirmation test with greater specificity.

Acquired Immunodeficiency Syndrome↗
PubMed1985

The detection of Jonah gene transcripts in Drosophila by in situ hybridization.

The Jonah genes constitute a family of approximately 20 genes expressed at two periods during the development of Drosophila melanogaster. They are expressed only in the midgut, where they yield very abundant transcripts of approximately 900 bases. The function of their products is not known. We have used in situ hybridization to show that transcripts homologous to two members of the Jonah family have quite different distributions within the midgut. Transcripts closely homologous to Jon65Aiv are expressed throughout most of the anterior midgut and in the posterior section of the middle midgut. Transcripts closely homologous to Jon99C beta are expressed only in the anterior region of the posterior midgut.

Animals↗
PubMed1985

The Jonah genes: a new multigene family in Drosophila melanogaster.

The Jonah gene family consists of approximately 20 genes, distributed in small clusters at eight or more widely dispersed chromosomal sites. Gene clusters differ in the number of genes per cluster, ranging up to four, and in the arrangement of genes within clusters, which include direct repeats, inverted repeats, and combinations of direct and inverted repeats. In the third-instar larva the Jonah genes are abundantly expressed as transcripts of a single size class, located exclusively in the midgut. The Jonah genes were initially defined by homology to a reference cDNA clone. However, the structural heterogeneity within this gene family is so large that Jonah genes that fail to hybridize to the reference cDNA, yet hybridize to other members of the family that do hybridize to that cDNA have been subsequently identified. These findings raise questions regarding the sharpness of gene family boundaries.

Animals↗
PubMed1985

Developmental and functional analysis of Jonah gene expression.

The Jonah genes are expressed twice in development: Jonah RNA is detected during all larval stages, disappears at the end of the third larval instar, and then reappears shortly after eclosion, in the adult midgut. Construction and analysis of Jonah cDNA clones reveals that multiple Jonah genes are transcribed; cDNA clones deriving from at least four different clusters of Jonah genes have been identified. In at least one case, multiple genes in a cluster are transcribed, and one cluster is found to be transcribed both in larvae and adults. Evidence that different Jonah genes are under different control with respect to both spatial and temporal patterns of expression has been provided. Jonah RNA encodes a 28-kDa translation product or products for which we consider a possible function. Jonah RNA of constant length is found to be conserved in all strains of Drosophila melanogaster examined, Jonah genes are found at a minimum of three common chromosomal sites in all of seven D. melanogaster strains examined, and multiple Jonah genes are found in other Drosophila species.

Animals↗
PubMed1985

Glutathione adduct formation with microsomally activated metabolites of the pulmonary alkylating and cytotoxic agent, 3-methylindole.

Incubations with goat lung and liver microsomes were conducted to trap with exogenous glutathione (GSH) the electrophilic intermediate produced via cytochrome P-450-dependent metabolic activation of 3-methylindole (3MI). Microsomal incubation mixtures with [14C]3MI, a NADPH-generating system, and [3H]GSH produced a dual-labeled adduct which was isolated by reverse-phase high-performance liquid chromatography. Reactive 3MI intermediates were also trapped with cysteine. Adduct formation increased in proportion to the concentration of either thiol. Covalent binding of activated 3MI metabolites to microsomal protein was inversely related to adduct production. There were both qualitative and quantitative differences in the formation of GSH adducts by lung and liver microsomes. In the presence of 2 mM GSH, the adduct was produced at a rate of 1.8 nmol/mg protein/min by lung microsomes but only at 0.1 nmol/mg protein/min by hepatic microsomes. The addition of cytosolic fractions containing glutathione S-transferase activity increased GSH adduct formation by approximately 30%. These results support the view that electrophilic 3MI intermediates are trapped by conjugation with GSH, and that organ-selective toxicity is primarily due to much faster rates of cytochrome P-450 oxidation of 3MI in the lung than in the liver.

Alkylating Agents↗
PubMed1985

Adducts of 3-methylindole and glutathione: species differences in organ-selective bioactivation.

Lung and liver microsomes of several species were evaluated for potential to form activated metabolites of 3-methylindole (3MI). Microsomes were incubated with [14C]3MI and glutathione (GSH). Electrophilic 3MI metabolites were trapped and quantitated as GSH adducts by HPLC, and by determining the amounts of activated intermediates which became covalently bound to microsomal protein. The highest rates of 3MI-GSH adduct formation by the lung were detected in microsomes of the goat, followed in decreasing order by pulmonary microsomes from the horse, monkey, mouse, and rat, respectively. In contrast, hepatic 3MI-GSH adduct production was highest in microsomes from the rat, followed by mouse, monkey, goat, and horse microsomes, respectively. These results suggest that the species and organ-selective toxicity of 3MI are primarily caused by differences in rates of oxidative metabolism of 3MI to an electrophilic intermediate.

Animals↗
PubMed1985

Alkylation of bronchiolar epithelial cells by 3-methylindole metabolites in the horse.

Autoradiographs of horse-lung explants incubated with [3H]3-methylindole (3MI) showed 8 times greater labeling per area to bronchiolar epithelial cells than to the interalveolar septa. Incubations of horse-lung microsomes with [14C]3MI resulted in alkylation of microsomal proteins, which could be reduced by exogenous glutathione. An apparent covalent adduct of glutathione and 3MI was isolated from these incubations. These results suggest that the target cells of 3MI-induced injury in the horse, the bronchiolar epithelial cells, are alkylated by an electrophilic 3MI intermediate.

Alkylation↗
PubMed1985

Evaluation of the RIM system and Gono Gen test for identification of Neisseria gonorrhoeae from clinical specimens.

RIM-N (Austin Biological Laboratories) and Gono Gen (Micro Media Systems) were evaluated for accuracy and compared with conventional carbohydrate degradation tests for identification of Neisseria gonorrhoeae. A total of 127 fresh clinical isolates of N. gonorrhoeae were tested; 118 (93%) were identified by RIM-N, and 100 (79%) yielded positive reactions with Gono Gen. Seventy nongonococcal isolates including other Neisseria species, Branhamella catarrhalis, Kingella kingae, and Moraxella species were evaluated to determine the specificity of the test methods. Both rapid tests were 100% specific in the identification of N. gonorrhoeae isolates. RIM-N was the most sensitive test for the identification of N. gonorrhoeae and offers a useful, more rapid alternative to conventional carbohydrate degradation methods.

Agglutination Tests↗
PubMed1985

Reactivity of serologic tests for the detection of antibody specific to cytomegalovirus.

A total of 212 sera were assayed for antibody specific for cytomegalovirus by complement fixation (CF), indirect immunofluorescence (IFA Electro-Nucleonics Laboratory, Inc., Bethesda, MD), ELISA (Cordis Laboratories, Inc., Miami, FL) and the FIAX system (International Diagnostic Technology, Santa Clara, CA). Correlation of CF with IFA, ELISA, and FIAX was 61%, 78%, and 71%, respectively. Quantitative correlation between IFA and FIAX and ELISA was not possible because of the broad range of reaction intensity of the latter two tests in sera with a particular IFA titer.

Antibodies, Viral↗
PubMed1985

Improved recovery of group A beta-hemolytic streptococci with a new selective medium.

A new selective group A streptococcus agar (ssA) (BBL Microbiology Systems, Cockeysville, Md.) was evaluated for the recovery and direct plate identification of group A beta-hemolytic streptococci (GABHS) in comparison with sheep blood agar (SBA). A total of 265 GABHS were recovered from 1,116 throat swab specimens on both media, with detection rates of 98.9 and 91.7% for ssA and SBA, respectively. Primary bacitracin disk susceptibility tests were performed on 549 specimens, and presumptive identifications were possible for 81.4% of the GABHS on ssA, as compared with 44.2% on SBA. All of the 120 GABHS recovered from another 567 specimens were identified by a coagglutination method after overnight incubation on ssA, whereas only 70.2% were identified at this interval on SBA. The major advantage of the ssA was the inhibition of normal respiratory flora, permitting improved recovery and rapid identification of GABHS.

Culture Media↗
PubMed1985

Duration of inhibition of 3-methylindole production by monensin.

A series of in vitro and in vivo trials was conducted to determine if continuous monensin feeding for up to 56 d would reduce ruminal conversion of L-tryptophan (TRP) to 3-methylindole (3MI). Fourteen mature beef cows were adapted to a maintenance diet for 3 wk. In trial I, the sampling time to optimize 3MI production was determined. Trials II through IV were to determine the duration of efficacy of monensin on reducing 3MI concentrations in vitro and in vivo. During trials II, III and IV one-half of the cows were fed 200 mg monensin X head-1 X d-1 for 21, 36 and 55 d, respectively, while the remaining cows served as controls. All cows were fed the control diet for 21 d between each trial. Volatile fatty acid (VFA) concentrations and in vitro conversion of TRP to 3MI were determined in ruminal fluid samples collected during trials I through IV. On d 28 of trial IV, all cows were given an oral dose of .35 g TRP/kg of body weight to induce acute bovine pulmonary edema and emphysema (ABPE). Ruminal concentrations of 3MI and indole were measured at intervals for 96 h. Results of trial I demonstrated that ruminal fluid collected 15 h postfeeding produced the highest in vitro conversion of TRP to 3MI. Therefore, ruminal fluid samples were collected at that time in trials II, III and IV. In vitro conversion of TRP to 3MI was lower (P less than .01) in samples from monensin-treated cows (12.1%) compared with controls (25.6%). Monensin reduced 3MI production for 55 d, the longest time tested in these experiments.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗