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Biomedical subjects

C Rodgers

Publications and source records attributed to C Rodgers.

At least 37 records · Page 2Linked to original sources
PubMed1992

Extrapyramidal side effects of antiemetics presenting as psychiatric illness.

Although extrapyramidal side effects of two commonly used antiemetics, metoclopramide and prochlorperazine, are well known, it may be difficult for even the experienced practitioner to distinguish some of these extrapyramidal reactions from such psychiatric symptoms as anxiety, depression, or catatonia. Certain patient groups have increased susceptibility to these extrapyramidal reactions, including patients under 30, those with AIDS, those with renal disease, oncology patients, and possibly women. Physicians should maintain a high index of suspicion for depression, anxiety, or catatonia if their patients are taking antiemetics. These symptoms may be extrapyramidal side effects of the antiemetic rather than indications of a primary mental disorder.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Physical and functional characterization of the gene cluster encoding the polyketide phytotoxin coronatine in Pseudomonas syringae pv. glycinea.

Pseudomonas syringae pv. glycinea PG4180 produces the polyketide phytotoxin coronatine. The coronatine synthesis genes in PG4180 were previously shown to reside on a 90-kb plasmid designated p4180A. In the present study, clones containing a 34-kb region of p4180A were saturated with Tn5, and 71 unique mutations were recombined into p4180A by marker exchange. The effect of each mutation on coronatine synthesis was determined by analyzing the organic acids produced by the mutants by reverse-phase high-performance liquid chromatography. The organic acids of selected mutants were derivatized to their methyl esters and analyzed by gas chromatography and gas chromatography-mass spectrometry. Mutations in a 20.5-kb region of p4180A completely blocked the synthesis of coronafacic acid and coronatine. Mutations within a 4.4-kb region of p4180A prevented the formation of coronatine but allowed for production of coronafacic acid, coronafacoylvaline, coronafacoylisoleucine, and coronafacoylalloisoleucine. The phenotypes of selected mutants were further confirmed in feeding experiments in which coronafacic acid or coronamic acid was added to the culture media. The results of this study allow us to speculate on the likely sequence of steps in the later stages of coronatine biosynthesis.

Amino Acids↗
PubMed1989

Chromosomal aberrations and sister chromatid exchange tests in Chinese hamster ovary cells in vitro. IV. Results with 15 chemicals.

The National Toxicology Program has undertaken a study to assess the ability of four genetic toxicology assays to predict the carcinogenicity of chemicals in 2-year rodent studies [Tennant et al.: Science 236:933-941, 1987]. Two of the assays, used for evaluating in vitro cytogenetic damage, were the SCE and chromosome aberration assays in Chinese hamster ovary cells. The results and data for 15 of the chemicals tested in these two assays are presented here. Each chemical was tested with and without exogenous metabolic activation. The chemicals tested were bisphenol A, 2-chloroethanol, C.I. acid orange 10, C.I. disperse yellow 3, C.I. solvent yellow 14, cytembena, D&C red 9, 1,2-dibromoethane, FD&C yellow 6, malaoxon, D,L-menthol, phenol, sulfisoxazole, titanium dioxide, and tris(2-ethylhexyl)phosphate. In vitro cytogenetic results from the other chemicals presented by Tennant et al. (Science 236:933-941, 1987) have been published by Galloway et al. (Environmental and Molecular Mutagenesis 10(Suppl 10): 1-175, 1987), Gulati et al. (Environmental and Molecular Mutagenesis 13:133-193, 1989), and Love-day et al. (Environmental Mutagenesis 13:60-94).

Animals↗
PubMed1988

c-myc antisense transcripts accelerate differentiation and inhibit G1 progression in murine erythroleukemia cells.

Friend murine erythroleukemia (F-MEL) cells were transfected with a plasmid bearing tandemly arranged mouse c-myc antisense and dihydrofolate reductase transcription units. Sixteen clones were isolated, each containing unrearranged c-myc sequences and expressing high levels of antisense transcripts. All antisense clones examined contained reduced amounts of cytoplasmic endogenous c-myc transcripts. The kinetics of reaccumulation of endogenous c-myc mRNA during a 24-h exposure to dimethyl sulfoxide (DMSO) were also retarded and the ultimate transcript levels attained were less than in control cells. Antisense clones grew as well as control F-MEL cells in medium containing 10% fetal calf serum but at only a half and a quarter of the control rates in media containing 5 and 2% serum, respectively. Antisense clones differentiated faster and to a greater degree than control cells following DMSO exposure. myc antisense transcript expression was increased by growing cells in methotrexate, which resulted in an enhanced response to DMSO. Fluorescence-activated cell sorter (FACS) analysis of cellular DNA content indicated that a greater fraction of antisense nuclei contained a G0/G1 2n DNA content following a 24-h exposure to DMSO. When density-arrested antisense clones were diluted into fresh medium to allow reentry into the cell cycle, they incorporated less [3H]thymidine than control cells. FACS analysis showed that this was because only a portion of the cell population was entering S phase. Whereas control cells did not increase in size following release from density arrested antisense cells contained a subpopulation which were initially smaller and which eventually attained the same size as control cells. Quiescent antisense cells thus comprise two populations, each arrested at a different point in G1. Dilutional replating allowed both populations to reenter the cell cycle. We propose a model which postulates that certain minimal myc levels are necessary for cells to traverse G1. Those with insufficient levels, due, for example, to antisense inhibition, are unable to completely traverse G1 during density arrest and synchronize at an earlier point than do control cells. This earlier point may be along the differentiation pathway and may account for the greater responsiveness of antisense cells to DMSO induction. This model postulates that F-MEL cells overexpressing myc fail to differentiate because myc levels are never sufficiently low enough to allow cells to enter the differentiation pathway.

Animals↗
PubMed1988

Repeal of the Massachusetts seat belt law.

In November 1986, the Massachusetts mandatory seat belt use law repealed in a referendum by a 53 per cent to 47 per cent vote. In an anonymous random digit telephone survey of 1,046 adults in Massachusetts in summer 1986, while the law was in effect, 61 per cent of respondents had said they would vote in favor of the law. A post-repeal follow-up of 80 per cent of these persons revealed initial supporters and opponents of the law were equally likely to vote, but 15 per cent of the summer supporters switched their opinions and voted for repeal, compared to only 4 per cent of summer opponents who switched. In addition, a separate survey of 167 households that had refused to answer the summer survey indicated that survey nonrespondents were more likely to vote against the law than for it. Those opposing the law saw it as an infringement on personal liberty and believed it was not effective in reducing injury and death.

Choice Behavior↗
PubMed1987

Maternal support for the Down's syndrome stereotype: the effect of direct experience of the condition.

Maternal agreement with the Down's syndrome stereotype (as outlined in the literature) was investigated as a function of direct experience of the condition. Using an adjective checklist devised for this project, mothers of children aged between 3 and 9 years were asked to describe Down's children. Statistical analysis of the data collected revealed that familiarity with the condition resulted in a broader general stereotype (represented by the number of adjectives endorsed). Specifically, mothers of Down's Syndrome children attributed more personality traits to the Down's child than mothers without direct experience of the condition. Mothers of such children also claimed a wider range of personality characteristics for their own child than for Down's children in general. Implications for future research were discussed, as was the value of 'normalization' and increased contact with normal peers in the education and integration into the community of Down's children.

Adult↗
PubMed1986

Proposed pathogenic mechanism for the diarrhea associated with human intestinal spirochetes.

Spirochetes resembling Brachyspira aalborgi were found in the feces and rectal biopsies of a patient with persistent diarrhea. Although the organism failed to grow on bacteriologic media, it was found attached to the surfaces of the epithelial cells on the rectal lumen. Blunting and destruction of the cellular microvilli was evident. These induced pathologic cell surface changes, together with the presence of intracellular bacteria in the cells of the rectal colon, suggest a pathogenic mechanism for the persistent diarrhea often associated with this condition. Both the spirochetosis and clinical symptoms disappeared on treatment with metronidazole.

Adolescent↗
PubMed1986

Assessment of some shock absorbing insoles.

Due to the increase in prescription of insoles to relieve symptoms due to skeletal shocks at heel strike a pilot study was initiated to look at some materials used for this purpose. Five materials were examined (Plastazote, Spenco, Sorbothane, Poron (PPT) and Viscolas) by two methods. The first method used an accelerometer mounted between the teeth of one of the authors (PR) to record skeletal shock. The second method used a force plate to record the shock produced by dropping a ball-bearing onto the insoles from a standard height. The results showed that Plastazote is poor at absorbing shock with Spenco and Sorbothane being quite good. The best insole materials tested were Poron (PPT) and Viscolas with the latter being marginally superior. No account was taken of degradation of the materials in use except that Plastazote worn for 72 hours was also used in the study, this producing the worst results.

Evaluation Studies as Topic↗
PubMedDate not supplied

Pain and disability in families of chronic noncancer pain patients.

The authors conducted a cross-sectional study to determine the prevalence of chronic noncancer pain or disability in first-degree relatives of patients who had sustained a physically traumatic injury with resultant chronic pain. A control group of general internal medicine patients was also interviewed about existence in their family of chronic pain or of disability, either pain-related or related to nonpainful chronic illness. None of the control patients were themselves experiencing acute or chronic pain. There was no statistically significant difference between the two groups in the prevalence of chronic pain or disability in family members. The study's findings suggest that chronic noncancer pain patients should not be viewed as a uniform group with regard to learned behaviors and/or familial aggregation.

Adult↗
PubMedDate not supplied

Impact of pregnancy during training on a psychiatric resident cohort.

The issues surrounding pregnancy during residency training include length of maternity leave, coverage during that leave, and relationships among resident colleagues. With more women entering medicine, the likelihood of a majority of residents in any postgraduate year being pregnant at one time has increased. This study presents an in-depth view of one such resident cohort. Conflicts occurred over the perception that pregnant residents received special treatment. The defenses mobilized by residents included projection and denial.

Adult↗