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Biomedical subjects

C Coulter

Publications and source records attributed to C Coulter.

At least 19 recordsLinked to original sources
PubMed2001

Effects of resistance exercise and creatine supplementation on myasthenia gravis: a case study.

PURPOSE: The purpose of this case study was to determine the effects of 15 wk of resistance exercise and creatine (Cr) supplementation on body composition, training volume, peak strength, and complete blood chemistry in a patient with myasthenia gravis (MG). METHODS: The patient was a 26-yr-old man who was taking prednisone and azathioprine for his condition. The patient self-administered 5 g of Cr per day in addition to resistance exercise 3 times per week. Fasting blood samples were obtained and body weight (BW) and fat free mass (FFM; via hydrostatic weighing) were measured before and after training and Cr supplementation. In addition, isokinetic (Cybex II) peak strength for leg extension (LE), leg flexion (LF), and volume load (repetition x mass lifted) for the first and last resistance training session were determined. RESULTS: After Cr supplementation and training, the results demonstrated increases in BW (6.8%), FFM (4.3%), upper body volume load (37.0%), lower body volume load (15.0%), and peak strength for LE (37.0%) and LF (12.5%). Moreover, blood chemistry values remained within normal limits for the duration of the 15-wk study. CONCLUSION: These data suggest that resistance exercise plus Cr supplementation may promote gains in strength and FFM in patients with MG.

Adult↗
PubMed2001

Functional imaging as an aid to decision-making in metastatic paraganglioma.

Malignant paraganglioma is a rare and slow growing tumour of neuroendocrine origin. At the time of diagnosis, the tumour is usually widespread, with limited therapeutic options. A variety of functional imaging studies are available for staging the disease, guiding therapy and monitoring treatment response. These include 123I-MIBG or 131I-MIBG, 111In-pentetreotide or 111In-lanreotide (somatostatin analogues), and 18F-FDG positron emission tomography. Various radionuclides, including 131I and 90Y, can be targeted to the tumour using MIBG or pentetreotide. Such targeted radionuclide therapy may provide valuable long-term palliation in such patients. We present two cases with metastatic paragangliomas who had widespread soft tissue and bone metastases. One patient was treatment naive and the second had received previous chemotherapy. The functional imaging work-up performed and the targeted radionuclide therapies considered in these patients are described. Both patients were treated with 131I-MIBG. Partial tumour response and complete symptomatic and hormonal response was achieved in one patient; in the second patient there was no change.

3-Iodobenzylguanidine↗
PubMed1999

Rubella infection in pregnancy.

It is over 50 years since a syndrome of congenital abnormalities following maternal rubella infection was first recognised. Despite the potentially devastating effects of the congenital rubella syndrome, immunisation rates are not optimal and infections in pregnancy still occur. Four cases of rubella infection occurring in pregnancy are presented. Laboratory diagnosis of primary infection and reinfection is discussed, and the need for full immunisation in childhood, and of women of child-bearing age is reiterated.

Adult↗
PubMed1999

Halomethane:bisulfide/halide ion methyltransferase, an unusual corrinoid enzyme of environmental significance isolated from an aerobic methylotroph using chloromethane as the sole carbon source.

A novel dehalogenating/transhalogenating enzyme, halomethane:bisulfide/halide ion methyltransferase, has been isolated from the facultatively methylotrophic bacterium strain CC495, which uses chloromethane (CH(3)Cl) as the sole carbon source. Purification of the enzyme to homogeneity was achieved in high yield by anion-exchange chromatography and gel filtration. The methyltransferase was composed of a 67-kDa protein with a corrinoid-bound cobalt atom. The purified enzyme was inactive but was activated by preincubation with 5 mM dithiothreitol and 0.5 mM CH(3)Cl; then it catalyzed methyl transfer from CH(3)Cl, CH(3)Br, or CH(3)I to the following acceptor ions (in order of decreasing efficacy): I(-), HS(-), Cl(-), Br(-), NO(2)(-), CN(-), and SCN(-). Spectral analysis indicated that cobalt in the native enzyme existed as cob(II)alamin, which upon activation was reduced to the cob(I)alamin state and then was oxidized to methyl cob(III)alamin. During catalysis, the enzyme shuttles between the methyl cob(III)alamin and cob(I)alamin states, being alternately demethylated by the acceptor ion and remethylated by halomethane. Mechanistically the methyltransferase shows features in common with cobalamin-dependent methionine synthase from Escherichia coli. However, the failure of specific inhibitors of methionine synthase such as propyl iodide, N(2)O, and Hg(2+) to affect the methyltransferase suggests significant differences. During CH(3)Cl degradation by strain CC495, the physiological acceptor ion for the enzyme is probably HS(-), a hypothesis supported by the detection in cell extracts of methanethiol oxidase and formaldehyde dehydrogenase activities which provide a metabolic route to formate. 16S rRNA sequence analysis indicated that strain CC495 clusters with Rhizobium spp. in the alpha subdivision of the Proteobacteria and is closely related to strain IMB-1, a recently isolated CH(3)Br-degrading bacterium (T. L. Connell Hancock, A. M. Costello, M. E. Lidstrom, and R. S. Oremland, Appl. Environ. Microbiol. 64:2899-2905, 1998). The presence of this methyltransferase in bacterial populations in soil and sediments, if widespread, has important environmental implications.

Amino Acid Sequence↗
PubMed1997

Altered wound arginine metabolism by corticosterone and retinoic acid.

Arginine metabolism plays an important role in many aspects of inflammation and wound healing. In this study, we tested the hypothesis that steroids and vitamin A have differential effects on arginine metabolism and thereby may provide a mechanism by which steroids impair wound healing, and vitamin A improves this impairment. Rats were treated with subcutaneous corticosterone pellets 2 days prior to wounding. Intraperitoneal injections of all-trans retinoic acid in peanut oil were administered at the same time and repeated 2 and 4 days later. Polyvinyl alcohol sponges were implanted subcutaneously through a dorsal incision. On Postwounding Days 1, 5, 10, and 15, wound fluid was recovered from the sponges and assayed for nitrite/nitrate (NOx), citrulline, arginine, and ornithine concentrations as well as arginase activity. Steroid treatment decreased the metabolism of arginine to nitric oxide in the early phase of wound healing, and retinoic acid did not change this relationship. Corticosterone also decreased metabolism of arginine to ornithine in the later wound. This depression was inhibited by concomitant administration of retinoic acid. Considering the importance of nitric oxide in host defense and ornithine as a precursor for polyamine and proline synthesis, these data provide a mechanism by which vitamin A improves wound strength, but does not improve wound infection rates in steroid-treated animals.

Animals↗
PubMed1993

Evidence for the existence of independent chloromethane- and S-adenosylmethionine-utilizing systems for methylation in Phanerochaete chrysosporium.

O methylation of acetovanillone at 4 position by C2H3Cl and S-adenosyl[methyl-2H3]methionine was monitored in whole mycelia of Phanerochaete chrysosporium in the presence and absence of S-adenosylhomocysteine. Both the amount of the methylation product, 3,4-dimethoxyacetophenone, and the percent C2H3 incorporation into the 4-methoxyl group of the compound were determined. The results strongly suggest the presence of biochemically distinct systems for O methylation of acetovanillone utilizing S-adenosylmethionine and chloromethane, respectively, as the methyl donor. The S-adenosylmethionine-dependent enzyme is induced early in the growth cycle, with activity attaining an initial maximum after 55 h of incubation. Methylation by this enzyme is totally suppressed by 1 mM S-adenosylhomocysteine over almost the entire growth cycle. S-Adenosylmethionine-dependent O-methyltransferase activity is detectable in cell extracts, and the purification and characterization of the enzyme are described elsewhere (C. Coulter, J. T. Kennedy, W. C. McRoberts, and D. B. Harper, Appl. Environ. Microbiol. 59:706-711, 1993). The chloromethane-utilizing methylation system is absent in early growth but attains peak activity in the mid-growth phase after 72 h of incubation. The system is not significantly inhibited by S-adenosylhomocysteine at any stage of growth. No chloromethane-dependent O-methyltransferase activity is detectable in cell extract, suggesting that the enzyme is membrane bound and/or part of a multienzyme complex. Although the biochemical role of the chloromethane-dependent methylation system in metabolism is not known, one possible function could be the regeneration of veratryl alcohol degraded by the attack of lignin peroxidase.

Acetophenones↗
PubMed1993

Gram-negative meningitis and chronic constipation: an unusual presentation of caudal regression syndrome.

Congenital malformations may present as meningitis caused by enteric organisms, but this is extremely rare and occurs almost exclusively in the paediatric population. We report an unusual case of a young man with chronic constipation presenting with spontaneous Gram-negative meningitis due to an underlying congenital spinal malformation known as the caudal regression syndrome.

Abnormalities, Multiple↗
PubMed1992

Successful treatment of disseminated strongyloidiasis.

OBJECTIVE: To report the successful treatment of Strongyloides stercoralis hyperinfection, which is usually lethal but in this case was diagnosed in its early stages. CLINICAL FEATURES: A 44-year-old woman, who had spent much of her life in Fiji and India, was treated with a high dose of prednisolone for rheumatoid arthritis complicated by gold lung. The onset of abdominal symptoms, an exacerbation of respiratory symptoms, and a persistent high eosinophil count and serum IgE level, led to the detection of numerous Strongyloides larvae in her faeces and sputum. INTERVENTION AND OUTCOME: She was treated with thiabendazole for five days, then mebendazole for one month, and the dose of prednisolone was reduced. Clinical symptoms and signs improved within days and after one week parasites could not be found in her faeces. After six months, enzyme-linked immunosorbent assay for Strongyloides infection gave a reading which was 40% of the initial level but still in the positive range. CONCLUSION: Steroid therapy in individuals with chronic, subclinical strongyloidiasis predisposes to the insidious development of hyperinfection syndrome, which has a high mortality rate. If detected early, this complication can be treated effectively. It can be prevented by actively seeking Strongyloides infection, by faecal microscopy and culture techniques and by serological tests, in high-risk individuals, such as immigrants from endemic areas.

Adult↗
PubMed1990

Intraperitoneally administered 90Y-labelled monoclonal antibodies as a third line of treatment in ovarian cancer. A phase 1-2 trial: problems encountered and possible solutions.

A phase 1-2 trial of 90Y-labelled monoclonal antibody, HMFG1 administered intraperitoneally to 30 patients with ovarian carcinoma is presented. The problems encountered with myelotoxicity are described, and the steps which have so far been taken to overcome this and to increase the dose of 90Y to an estimated tumouricidal level. Bone deposition of free 90Y limits the dose which can be administered without severe bone marrow toxicity. The intravenous use of a chelating agent, Ledclair (EDTA) has allowed the dose to be increased from 18 to 30 mCi without causing severe myelotoxicity. 90Y-DTPA MAb is an unstable immunoconjugate in vivo and in vitro. The use of a more stable linkage such as a macrocycle should enable the administered dose to be increased without increasing the amount of free 90Y which becomes available to be deposited in bone. This would be expected to reduce toxicity and increase therapeutic efficacy.

Antibodies, Monoclonal↗
PubMed1989

Shared idiotypes expressed by human B-cell lymphomas.

Each B-cell lymphoma expresses a surface immunoglobulin that contains unique antigenic determinants (idiotypes). We have produced 199 murine monoclonal antibodies reactive with the idiotypes isolated from 67 patients with follicular small-cleaved-cell lymphoma. These antiidiotype antibodies were analyzed for their ability to react with lymphoma cells from patients other than the one against which each antibody was made. Twenty of the 199 antiidiotype antibodies were reactive with lymphoma cells from more than one patient. Depending on the antibody, the frequency of idiotype sharing ranged from 0.6 to 6.2 percent of B-cell lymphoma tumors evaluated. Tumors could be grouped into distinct families on the basis of their reactivity with these antibodies. In the aggregate, the 20 antibodies reacted with a total of 49 of 150 B-cell lymphomas (33 percent), including 30 of 110 follicular small-cleaved-cell lymphomas (27 percent). Many of these shared idiotypes were expressed by more than one histopathological subtype of lymphoma. We conclude that a panel of antibodies reactive with shared idiotypes can be produced for patients with B-cell lymphoma, obviating the need to produce an antiidiotype antibody for each patient.

Antibodies, Anti-Idiotypic↗
PubMed1987

Binding of the pseudorabies virus immediate-early protein to single-stranded DNA.

In an attempt to correlate the ability to activate transcription with affinity for single-stranded DNA, both wild-type and temperature-sensitive pseudorabies virus immediate-early proteins were tested for the ability to bind to single-stranded DNA columns. Wild-type and temperature-sensitive immediate-early proteins bound to nonspecific single-stranded DNA columns with similar affinities at both 0 and 40 degrees C. There did not seem to be a direct correlation between the ability to activate transcription and the ability to bind to single-stranded DNA. To study further the interactions that are involved in binding to single-stranded DNA, we expressed the immediate-early protein in an Escherichia coli expression vector. In this system the expressed immediate-early protein was not phosphorylated, nor could it be complexed with mammalian cell factors. The first trp construct did not express a soluble form of the immediate-early protein, presumably due to the insoluble nature of the trp leader. We deleted a large segment of the trpE gene and found that the immediate-early fusion protein was soluble. We tested this protein for its affinity for single-stranded DNA by passage over single-stranded DNA cellulose columns. The bacterially expressed immediate-early protein bound single-stranded DNA at least as well as did the wild-type protein. Affinity for single-stranded DNA did not appear to be dependent on the phosphorylation state nor on the presence of mammalian cell factors.

Chromatography, Affinity↗