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Thomas MJ, Hamman BN, Tibbits GF. Dihydropyridine and ryanodine binding in ventricles from rat, trout, dogfish and hagfish. J Exp Biol 1996; 199:1999-2009. [PMID: 8831145 DOI: 10.1242/jeb.199.9.1999] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the adult mammalian heart, the majority of Ca2+ required for contraction is released from the sarcoplasmic reticulum (SR) via the Ca2+-release channel or ryanodine receptor (RyR). Such release is dependent upon a relatively small influx of Ca2+ entering the cell across the sarcolemma (SL) by means of the L-type Ca2+ channel or the dihydropyridine receptor (DHPR). In lower vertebrates, there is indirect evidence suggesting that Ca2+ influx across the SL may be sufficient to support contraction in the absence of Ca2+ release from the SR. This apparent difference in myocardial excitation-contraction (E-C) coupling was investigated further by determining DHPR and RyR densities in ventricular homogenate preparations from rat, trout, dogfish and hagfish. DHPR Bmax values (means +/- S.E.M.) were highest in rat (0.30 +/- 0.01 pmol mg-1), lower in trout (0.16 +/- 0.01 pmol mg-1) and dogfish (0.27 +/- 0.03 pmol mg-1), and slightly above the level of detection in hagfish (0.03 +/- 0.01 pmol mg-1). The DHPR dissociation constants (Kd) of 40-70 pmoll-1 in these three species were of similar magnitude. RyR binding revealed both high- and low-affinity sites in all species. RyR Bmax for the high-affinity site was greatest in the rat (0.68 pmol mg-1), lower in trout (0.19 pmol mg-1) and dogfish (0.07 pmol mg-1) and lowest in hagfish (0.01 pmol mg-1). The RyR Kd1 values for the high-affinity sites were comparable in all preparations (range 12-87 nmoll-1). The quantitative expression of RyRs in these species is consistent with the relative amount of SR present as indicated in physiological experiments and electron micrographs. Taking into consideration myocyte morphology of teleost and elasmobranch species, the data are consistent with a greater reliance on Ca2+ influx across the SL during E-C coupling in lower vertebrates, although a functional role for Ca2+ release from the SR in the more active species await further investigation.
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Thomas MJ, Parry ES, Nash SG, Bell SH. A method for the cryopreservation of red blood cells using hydroxyethyl starch as a cryoprotectant. TRANSFUSION SCIENCE 1996; 17:385-96. [PMID: 10163545 DOI: 10.1016/0955-3886(96)00009-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A simple, quick, inexpensive and long term method of cryopreserving human red cells using hydroxyethyl starch (HES) as a cryoprotectant is described. No sophisticated equipment or skilled labour is required. As HES is a plasma expander, it does not have to be removed prior to transfusion, thereby obviating the requirement for a washing stage. This allows 60 units/h to be prepared. As the microbiological integrity of the system is maintained, there is potential for prolonged storage post-thaw at 4 degrees C. Recoveries of 99% and 30 min saline stabilities in excess of 91% have been consistently achieved. P50O2 and 2,3DPG values are not significantly decreased.
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Thomas MJ, Moody TD, Makhinson M, O'Dell TJ. Activity-dependent beta-adrenergic modulation of low frequency stimulation induced LTP in the hippocampal CA1 region. Neuron 1996; 17:475-82. [PMID: 8816710 DOI: 10.1016/s0896-6273(00)80179-8] [Citation(s) in RCA: 236] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
beta-Adrenergic receptor activation has a central role in the enhancement of memory formation that occurs during heightened states of emotional arousal. Although beta-adrenergic receptor activation may enhance memory formation by modulating long-term potentiation (LTP), a candidate synaptic mechanism involved in memory formation, the cellular basis of this modulation is not fully understood. Here, we report that, in the CA1 region of the hippocampus, beta-adrenergic receptor activation selectively enables the induction of LTP during long trains of 5 Hz synaptic stimulation. Protein phosphatase inhibitors mimic the effects of beta-adrenergic receptor activation on 5 Hz stimulation-induced LTP, suggesting that activation of noradrenergic systems during emotional arousal may enhance memory formation by inhibiting protein phosphatases that normally oppose the induction of LTP.
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Thomas MJ. Royal College of Physicians of Edinburgh Consensus Conference on autologous transfusion: final consensus statement. TRANSFUSION SCIENCE 1996; 17:329-30. [PMID: 10163536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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105
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Chan EM, Thomas MJ, Bandy B, Tibbits GF. Effects of doxorubicin, 4'-epirubicin, and antioxidant enzymes on the contractility of isolated cardiomyocytes. Can J Physiol Pharmacol 1996. [DOI: 10.1139/y96-091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Chan EM, Thomas MJ, Bandy B, Tibbits GF. Effects of doxorubicin, 4'-epirubicin, and antioxidant enzymes on the contractility of isolated cardiomyocytes. Can J Physiol Pharmacol 1996; 74:904-10. [PMID: 8960379 DOI: 10.1139/cjpp-74-8-904] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The purpose of this study was to determine the acute effects of doxorubicin and its less cardiotoxic epimer, 4'-epirubicin, on the contractile response of isolated myocytes, and to assess similarities or differences with respect to active oxygen-derived mechanisms. Calcium-tolerant myocytes from rat ventricle were field stimulated at 1.0 Hz, and the maximum extent of cell shortening, peak shortening velocity, and peak relaxation velocity of single twitches were measured by video edge detection. The contractile responses of the myocytes to the two anthracyclines were approximately equal. Exposure of the cells to 10 microM of either anthracycline for 20 min decreased all indices of contractility by 28% (p < 0.05). The active oxygen scavengers, superoxide dismutase and catalase, distinguished the extent to which active oxygen was involved in modifying cellular contractility. Paradoxically, superoxide dismutase alone (10 U/mL) decreased contractility by 21%. Nevertheless, superoxide dismutase (10 U/mL) prevented the decreases in contractility produced by doxorubicin. In contrast, superoxide dismutase only mildly (32%) protected against 4'-epirubicin. Catalase (10 U/mL), however, provided substantial (82-93%) protection against both anthracyclines. Hydrogen peroxide therefore, and presumably hydroxyl radicals, were involved in mediating the decreases in contractility from both doxorubicin and 4'-epirubicin. These results show that an acute exposure to clinically relevant concentrations of these anthracyclines significantly depresses myocyte contractility and that, in this respect, 4'-epirubicin is as potentially cardiotoxic as doxorubicin. The results with antioxidant enzymes also strongly support a free radical mechanism for the toxicity of doxorubicin and 4'-epirubicin to cardiomyocytes.
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Gillon J, Thomas MJ, Desmond MJ. Consensus conference on autologous transfusion. Acute normovolaemic haemodilution. Transfusion 1996; 36:640-3. [PMID: 8701461 DOI: 10.1046/j.1537-2995.1996.36796323064.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
ANH is a relatively cheap and logistically straightforward method of autologous transfusion which is attractive in that it may be applied to a wide cross-section of patients, many of whom will not be suitable for pre-deposit. There are, however, concerns about the safety of the procedure, and doubts have been expressed about its efficacy in reducing allogeneic transfusion requirements and, therefore, its cost-effectiveness. Assessment of the value of the procedure is hampered by the lack of large scale prospective, controlled trials. In the present state of knowledge it seems that ANH is most likely to be safe, efficacious and cost-effective when undertaken aggressively (target haematocrit < 0.20) in otherwise healthy, young patients undergoing elective surgery with large expected blood losses.
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Desmond MJ, Thomas MJ, Gillon J, Fox MA. Consensus conference on autologous transfusion. Perioperative red cell salvage. Transfusion 1996; 36:644-51. [PMID: 8701462 DOI: 10.1046/j.1537-2995.1996.36796323065.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Thomas MJ, Gillon J, Desmond MJ. Consensus conference on autologous transfusion. Preoperative autologous donation. Transfusion 1996; 36:633-9. [PMID: 8701460 DOI: 10.1046/j.1537-2995.1996.36796323063.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Thomas MJ, Desmond MJ, Gillon J. Consensus conference on autologous transfusion. General background paper. Transfusion 1996; 36:628-32. [PMID: 8701459 DOI: 10.1046/j.1537-2995.1996.36796323062.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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112
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Brandwein M, Huvos AG, Dardick I, Thomas MJ, Theise ND. Noninvasive and minimally invasive carcinoma ex mixed tumor: a clinicopathologic and ploidy study of 12 patients with major salivary tumors of low (or no?) malignant potential. ORAL SURGERY, ORAL MEDICINE, ORAL PATHOLOGY, ORAL RADIOLOGY, AND ENDODONTICS 1996; 81:655-64. [PMID: 8784897 DOI: 10.1016/s1079-2104(96)80071-0] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We studied 12 histologically malignant salivary tumors that showed complete encapsulation or only limited microscopic invasion. Most cases were histologically characterized by atypical and mitotically active luminal cells forming dilated, angular, variably sized glands in the subcapsular region, varying proportions of nonluminal tumor cells, and a background of central fibrosed hyalinized stroma. The appearance is that of a low-grade carcinoma. Focal higher grade carcinoma was superimposed on this histologic data in three cases. Neither recurrences nor metastases were seen in 11 of 12 patients after surgical resection with a follow-up of 1.2 to 13 yrs (mean, 4.2 years). Ploidy studies were performed on the paraffin-embedded tissue in 11 cases and yielded results for 7 cases. Aneuploid cell populations were found in five tumors; two had normal diploid populations; and the ploidy results are not predictive of tumor behavior. This type of salivary gland tumor fits diagnostically within the category of noninvasive and minimally invasive carcinoma ex pleomorphic adenoma (also referred to as in situ and low-grade malignant mixed tumors), a class that requires additional awareness and precise recognition as it signifies a good prognosis after surgical resection.
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Thomas MJ, Rudel LL. Dietary fatty acids, low density lipoprotein composition and oxidation and primate atherosclerosis. J Nutr 1996; 126:1058S-62S. [PMID: 8642432 DOI: 10.1093/jn/126.suppl_4.1058s] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Low density lipoproteins (LDL) were isolated from nonhuman primates fed isocaloric diets rich in different types of fatty acids. These diets contained 35% of calories as fat enriched in fatty acids from the following sources: lard that is rich in saturated fatty acids, safflower oil rich in oleic acid, safflower oil rich in linoleic acid and menhaden oil that is rich in n-3 fatty acids. LDL composition reflected the dietary fats. LDL were subjected to oxidation using copper ions and azobis(2-amidinopropane) x 2HCl. In general, the sensitivity of LDL to oxidation depended on both the poly-unsaturated fatty acid and vitamin E content. However, the lag times calculated for the copper ion catalyzed oxidations did not show the linear dependence on vitamin E content that was found for azobis(2-amidinopropane) catalyzed oxidation.
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Thomas MJ. Royal College of Physicians, Edinburgh: final consensus statement. Consensus Conference on Autologous Transfusion, 4-6 October, 1995. Vox Sang 1996; 70:183-4. [PMID: 8740015 DOI: 10.1111/j.1423-0410.1996.tb01322.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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115
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Sorci-Thomas MG, Parks JS, Kearns MW, Pate GN, Zhang C, Thomas MJ. High level secretion of wild-type and mutant forms of human proapoA-I using baculovirus-mediated Sf-9 cell expression. J Lipid Res 1996; 37:673-83. [PMID: 8728328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
To facilitate the investigation of apoA-I structure:function relationships as they relate to LCAT activation and lipid binding, we have developed an apoA-I baculoviral expression and purification system that yields milligram quantities of wild-type or mutant proapoA-I. Baculovirus-infected Sf-9 cells, grown in suspension, were found to secrete high levels of human wild-type (40-50 mg/l) or mutant apoA-I protein (1-38 mg/l), which was determined to be > 95% pure following a two-step purification procedure. In the case of wild-type apoA-I, ELISA showed that approximately 13-18% of the total protein secreted into the culture medium was apoA-I. To isolate pure protein from culture medium, 72 h post-infection medium was subjected to preparative reverse phase high performance liquid chromatography (HPLC), followed by DEAE ion-exchange chromatography. Purity and molecular size determination of wild-type proapoA-I protein was verified by SDS polyacrylamide gel electrophoresis, electrospray mass spectrometry, and N-terminal sequencing. In addition, recombinant discoidal apoA-I:phospholipid complexes prepared from wild-type or plasma apoA-I showed similar particle size and LCAT activation properties. To fully characterize the utility of this expression system, the expression levels of various mutant apoA-I proteins were compared to wild-type. Despite a lower production level seen with selected apoA-I mutants, milligram quantities of these purified mutant proteins were also obtained. In summary, we show that baculovirus-derived wild-type proapoA-I shows properties similar to plasma apoA-I relative to recombinant HDL formation, LCAT reactivity, and alpha-helical content. In addition, we show that a variety of mutant forms of human proapoA-I can be expressed and purified in abundant quantity from baculoviral-infected Sf-9 cells.
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Thomas MJ. Controversies in the diagnosis and management of thyroid cancer. THE JOURNAL OF OTOLARYNGOLOGY 1996; 25:20-2. [PMID: 8816104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Kozumbo WJ, Hanley NM, Agarwal S, Thomas MJ, Madden MC. Products of ozonized arachidonic acid potentiate the formation of DNA single strand breaks in cultured human lung cells. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 1996; 27:185-195. [PMID: 8625954 DOI: 10.1002/(sici)1098-2280(1996)27:3<185::aid-em3>3.0.co;2-e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In this study we examined the potential for environmental levels of ozone (03) to degrade arachidonic acid (AA), a polyunsaturated fatty acid abundantly present in the lung, into products that can produce DNA single strand breaks (ssb) in cultured human lung cells. Human lung fibroblasts were incubated with 60 microM AA that had been previously exposed to and degraded by 0.4 ppm 03 (1 hr.) Incubation of the cells with 03-exposed AA (but not with vehicle alone) for 1 hr at 4 degrees C and 37 degrees C produced 555 and 245 rad-equivalents of DNA ssb, respectively, as determined by the DNA alkaline elution technique. These breaks were completely eliminated when the ozonized AA solution was incubated with catalase prior to cell treatment, indicating that h202 was solely responsible for damaging DNA. Superoxide dismutase bovine serum albumin, or heat-inactivated catalase showed little, if any, inhibitory activity. The H202 content of the ozonized AA (31 +/- 4 microM) could account for only about 40% of the observed breaks. Potentiation of the H202-induced DNA ssb persisted after removal of the carbonyl substances by chromatographic procedures, suggesting that the non-carbonyl component of ozonized AA was the responsible component for inducing augmentation of the observed increases in DNA ssb. Ozonized AA also induced DNA ssb in cultures of the human bronchial epithelial cell line BEAS-2B. Again, these breaks were shown to exceed levels that could be attributed to the presence of H202 alone. These results indicate that products of ozonized AA can interact to potentiate DNA ssb in human lung cells.
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Abstract
Rheumatoid factor is a commonly requested test in the investigation of joint problems. Although the test has been found to be both sensitive and specific for rheumatoid arthritis in patients attending Rheumatology Clinics, when the test is applied to general hospital or community populations it performs poorly. Thus the setting in which rheumatoid factor tests are requested and awareness of the test's limitations are critical for appropriate use and interpretation of results. We studied 295 consecutive requests for testing at four centres. The majority were performed for the investigation of joint problems but only 6% of these were positive, suggesting unselective requesting. Half of the results were used to make diagnoses and influence management. However, significant numbers of clinicians felt that the test result had either excluded or confirmed a diagnosis of rheumatoid arthritis suggesting that results were being over-interpreted and that clinical decisions made on this basis may have been inappropriate. We conclude that in this setting rheumatoid factor testing is of limited value and generates misleading information.
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Thomas MJ, O'Dell TJ. The molecular switch hypothesis fails to explain the inconsistent effects of the metabotropic glutamate receptor antagonist MCPG on long-term potentiation. Brain Res 1995; 695:45-52. [PMID: 8574646 DOI: 10.1016/0006-8993(95)00757-h] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In the CA1 region of the hippocampus, the induction of long-term potentiation (LTP) appears to be controlled by a switch-like biochemical process that is persistently activated following metabotropic glutamate receptor (mGLUR) activation. However, the mGLUR antagonist (RS)-alpha-methyl-4-carboxyphenylglycine (MCPG) does not consistently block the induction of LTP, perhaps because the experimental conditions used by some investigators inadvertently activate this 'molecular switch', thereby fulfilling the requirement for mGLUR activation and rendering LTP insensitive to the effects of mGLUR antagonists. In mouse hippocampal slices we observed that MCPG does not block LTP induced by high-frequency stimulation, Moreover, stimulation protocols designed to deactivate an inadvertently activated molecular switch had no effect on the inability of MCPG to block LTP. MCPG (through a switch-independent mechanism) did inhibit the induction of LTP by a weak induction protocol. Our results thus suggest that MCPT-sensitive mGLURs are not required for the induction of LTP and that a mLGUR-activated 'molecular switch' does not explain the inconsistent effects of MCPG on LTP. Instead, MCPG-sensitive mGLURs may have a modulatory role in the induction of LTP that is most evident when LTP is induced by near threshold patterns of synaptic stimulation.
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Poss KD, Thomas MJ, Ebralidze AK, O'Dell TJ, Tonegawa S. Hippocampal long-term potentiation is normal in heme oxygenase-2 mutant mice. Neuron 1995; 15:867-73. [PMID: 7576635 DOI: 10.1016/0896-6273(95)90177-9] [Citation(s) in RCA: 141] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We have generated mice deficient in HO-2, the major cerebral isoform of heme oxygenase, in order to assess the potential role of carbon monoxide as a retrograde messenger in hippocampal LTP. Cerebral HO catalytic activity was markedly reduced in the HO-2 mutant mice, yet no differences were found between wild types and mutants in gross neuroanatomical structure, in basal hippocampal synaptic transmission, or in the amount of potentiation produced by various LTP induction protocols. Furthermore, zinc protoporphyrin IX, an inhibitor of HO, had nearly identical inhibitory effects on LTP in wild-type and HO-2 mutant hippocampal slices. Our data indicate that carbon monoxide produced endogenously by HO is unlikely to be a neuromodulator required for LTP in the hippocampus.
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McCarthy TL, Thomas MJ, Centrella M, Rotwein P. Regulation of insulin-like growth factor I transcription by cyclic adenosine 3',5'-monophosphate (cAMP) in fetal rat bone cells through an element within exon 1: protein kinase A-dependent control without a consensus AMP response element. Endocrinology 1995; 136:3901-8. [PMID: 7649098 DOI: 10.1210/endo.136.9.7649098] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Insulin-like growth factor I (IGF-I) is a locally synthesized anabolic growth factor for bone. IGF-I synthesis by primary fetal rat osteoblasts (Ob) is stimulated by agents that increase the intracellular cAMP concentration, including prostaglandin E2 (PGE2). Previous studies with Ob cultures demonstrated that PGE2 enhanced IGF-I transcription through selective use of IGF-I promoter 1, with little effect on IGF-I messenger RNA half-life. Transient transfection of Ob cultures with an array of promoter 1-luciferase reporter fusion constructs has now allowed localization of a potential cis-acting promoter element(s) responsible for cAMP-stimulated gene expression to the 5'-untranslated region (5'-UTR) of IGF-I exon 1, within a segment lacking a consensus cAMP response element. Our evidence derives from three principal observations: 1) a transfection construct containing only 122 nucleotides (nt) of promoter 1 and 328 nt of the 5'-UTR retained full PGE2-stimulated reporter expression; 2) maximal PGE2-driven reporter expression required the presence of nt 196 to 328 of exon 1 when tested within the context of IGF-I promoter 1; 3) cotransfection of IGF-I promoter-luciferase-reporter constructs with a plasmid encoding the alpha-isoform of the catalytic subunit of murine cAMP-dependent protein kinase (PKA) produced results comparable to those seen with PGE2 treatment, whereas cotransfection with a plasmid encoding a mutant regulatory subunit of PKA that cannot bind cAMP blocked PGE2-induced reporter expression. Deoxyribonuclease I footprinting of the 5'-UTR of exon 1 demonstrated protected sequences at HS3A, HS3B, and HS3D, three of six DNA-protein binding sites previously characterized with rat liver nuclear extracts. Of these three regions, only the HS3D binding site is located within the functionally identified hormonally responsive segment of IGF-I exon 1. These results directly implicate PKA in the control of IGF-I gene transcription by PGE2 and identify a segment of IGF-I exon 1 as being essential for this hormonal regulation.
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Constans J, Peuchant E, Pellegrin JL, Sergeant C, Hamon C, Dubourg L, Thomas MJ, Simonoff M, Pellegrin I, Brossard G. Fatty acids and plasma antioxidants in HIV-positive patients: correlation with nutritional and immunological status. Clin Biochem 1995; 28:421-6. [PMID: 8521597 DOI: 10.1016/0009-9120(95)00017-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVE To investigate red blood cell (RBC) and plasma fatty acids (FA) in HIV-positive patients in relation to oxidative stress and nutritional or immunological status. DESIGN AND METHODS FA, plasma selenium, vitamins A and E were measured in 95 patients divided into four groups according to CD4 cells. RESULTS Poly- and di-unsaturated FA (PUFA, DUFA) decreased and saturated FA (SFA) increased in RBC in the patients below 400/mm3 and in plasma in the patients below 50/mm3. RBC SFA correlated to CD4 cells, PUFA to MDA. Unlike vitamin E, plasma vitamin A and selenium decreased in most groups. Plasma SFA and MUFA correlated negatively to selenium and PUFA and DUFA to vitamin E. No correlation was found between PUFA and nutritional markers. CONCLUSION FA seem to be modified during HIV infection by oxidative stress and disease evolution, but not by denutrition.
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Robison TW, Forman HJ, Thomas MJ. Release of aldehydes from rat alveolar macrophages exposed in vitro to low concentrations of nitrogen dioxide. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1256:334-40. [PMID: 7786896 DOI: 10.1016/0005-2760(95)00041-a] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
This study demonstrated that aldehydes are released into the extracellular medium when alveolar macrophages (AM) are exposed to nitrogen dioxide (NO2) at concentrations that impair cell function but do not cause cell death. Butanal, glycolaldehyde, 4-hydroxynonenal, pentanal, pentenal, and hexanal were found. Dinitrophenylhydrazine (DNP) derivitization, thin layer chromatography, high performance liquid chromatography, and gas chromatography-mass spectrometry were used to identify the products. Some of the aldehydes have potential toxicity and may be responsible, in part, for altered AM function observed following NO2 exposure.
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Le Stunff C, Thomas MJ, Rotwein P. Rapid activation of rat insulin-like growth factor-I gene transcription by growth hormone reveals no changes in deoxyribonucleic acid-protein interactions within the second promoter. Endocrinology 1995; 136:2230-7. [PMID: 7720672 DOI: 10.1210/endo.136.5.7720672] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Insulin-like growth factor-I (IGF-I) is a highly conserved 70-residue circulating peptide that mediates many of the systemic growth-promoting effects of GH. This laboratory has found previously that GH rapidly stimulates hepatic IGF-I transcription in hypophysectomized (hypox) rats by activating promoter 1, the major rat IGF-I gene promoter. In this study, the hormonal regulation of IGF-I expression through promoter 2, a minor promoter in most tissues but active in the liver, was investigated. Through use of a sensitive RNase protection assay, GH was shown to rapidly induce the accumulation of correctly initiated transcripts directed by this promoter in hepatic nuclei. Using in vitro DNase-I footprinting, six DNA-protein interactions were identified within promoter 2 with hepatic nuclear extracts from juvenile male hypox rats given a single ip injection of GH or saline 60 min before death. These DNA-protein-binding complexes also were investigated for specificity and for regulation by GH by gel mobility shift assays. All DNA-protein interactions were detected in hepatic nuclear protein extracts from hypox rats and did not change within 15-120 min after GH treatment. These results thus identify and characterize a series of constitutive nuclear protein-binding sites within the second rat IGF-I promoter that may be involved in mediating its transcriptional activity.
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Thomas MJ, Robison TW, Samuel M, Forman HJ. Detecting and identifying volatile aldehydes as dinitrophenylhydrazones using gas chromatography mass spectrometry. Free Radic Biol Med 1995; 18:553-7. [PMID: 9101246 DOI: 10.1016/0891-5849(94)e0121-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The detection of aldehydes has become an important measure of lipid oxidation in biological milieu. Aldehyde 2,4-dinitrophenylhydrazones are easily prepared and readily purified by HPLC and/or TLC and have proven useful for the detection of aldehydes. The lower limit of detection for dinitrophenylhydrazones was significantly reduced by using gas chromatography-mass spectrometric (GC-MS) techniques. Individual dinitrophenylhydrazones were readily separated by GC and detected by both positive and negative ion MS. The two major ions in negative ion spectra were the 182 m/z fragment ion and the molecular ion. Positive ion spectra showed strong ions corresponding to the protonated molecular ion and a protonated iminium ion. The greatest sensitivity was obtained with negative ion detection (10 pg per injection). However, more structural information was obtained from analysis of the positive ion spectra. Dinitrophenylhydrazones of hydroxyaldehydes, like 4-hydroxynonenal, were analyzed after converting the dinitrophenylhydrazones into trimethylsiloxylethers. GC-MS with negative ion detection was used to identify and quantitate the release of 4-hydroxynonenal by alveolar macrophages exposed to nitrogen dioxide.
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