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D C Galloway

Publications and source records attributed to D C Galloway.

17 recordsLinked to original sources
PubMed1999

Regulation of gamma-glutamylcysteine synthetase regulatory subunit (GLCLR) gene expression: identification of the major transcriptional start site in HT29 cells.

gamma-Glutamylcysteine synthetase (GCS) is of major importance in glutathione homeostasis. The GCS heterodimer is composed of catalytic (heavy subunit, GCSh) and regulatory (light subunit, GCSl) subunits. Regulation of the human GCSl subunit gene (GLCLR) expression was studied as GCSl has a critical role in glutathione synthesis. The minimal basal expression of GLCLR was found to be mediated by a region between nt -205 and -318. The major transcriptional start site in HT29 cells was located within this region at nt -283. A region between nt -411 and -447 was identified as having a potential involvement in the negative regulation of GLCLR expression. In order to study the transcriptional regulation of GCSl by oxidant stress, HepG2 cells were treated with sodium nitroprusside (SNP). SNP (1.5 mM) was found to increase glutathione levels by 2-fold, as well as GCS activity by 6-fold. This is accompanied by a co-ordinate increase in the levels of the both the GCSl and GCSh subunits, each by approximately 2-fold. The transcriptional activity of the GLCLR gene was increased by approximately 2.5-fold in SNP-treated cells.

Base Sequence↗
PubMed1998

Inducible expression of the gamma-glutamylcysteine synthetase light subunit by t-butylhydroquinone in HepG2 cells is not dependent on an antioxidant-responsive element.

Mutation analysis of putative regulatory elements located in the 5'-flanking region of the gene encoding the regulatory subunit of gamma-glutamylcysteine synthetase (GLCLR) revealed that neither an antioxidant-responsive element (ARE) nor an activator protein-1 (AP-1) site regulates inducible expression by t-butylhydroquinone (tBHQ). The AP-1 site was found to modulate basal expression of GLCLR. A 42 bp region between nucleotides -303 and -344, not containing an ARE, was found to regulate inducible expression of GLCLR by tBHQ.

Antioxidants↗
PubMed1997

Regulation of human gamma-glutamylcysteine synthetase: co-ordinate induction of the catalytic and regulatory subunits in HepG2 cells.

We have shown that in HepG2 cells treatment with 75 microM t-butylhydroquinone (tBHQ) results in a 2.5-fold increase in glutathione concentration, as part of an adaptive response to chemical stress. In these cells the elevation in intracellular glutathione level was found to be accompanied by an increase of between 2-fold and 3-fold in the level of the 73 kDa catalytic subunit of gamma-glutamylcysteine synthetase (heavy subunit, GCSh) and the 31 kDa regulatory subunit (light subunit, GCSl). Levels of GCSh and GCSl mRNA were increased by up to 5-fold in HepG2 cells in response to tBHQ. To study the transcriptional regulation of GCSl, we subcloned 6.7 kb of the upstream region of the human GCSl gene (GLCLR) from a genomic clone isolated from a P1 lymphoblastoid cell line genomic library. HepG2 cells were transfected with GLCLR promoter reporter constructs and treated with tBHQ. This resulted in an induction of between 1.5-fold and 3.5-fold in reporter activity, indicating that transcriptional regulation of GLCLR is likely to contribute to the induction of GCSl by tBHQ in HepG2 cells. Sequence analysis of the promoter region demonstrated the presence of putative enhancer elements including AP-1 sites and an antioxidant-responsive element, which might be involved in the observed induction of the GLCLR promoter.

Amino Acid Sequence↗
PubMed1987

Atypical CT pattern in multiple sclerosis.

We have reported a case of multiple sclerosis in which CT showed a large enhancing lesion with mass effect that was later found to be an acute demyelinating plaque. Magnetic resonance imaging showed other lesions in the centrum semiovale and periventricular areas bilaterally. The advent of magnetic resonance imaging permits diagnosis of atypical demyelinating processes in a less invasive and more direct manner.

Adult↗
PubMed1978

A study of the dose to the thyroid and the eye in computed tomography of the brain.

Thermoluminescent dosimeters were used to estimate the dose to the thyroid and the eye for routine clinical computed tomography of the brain using an EMI CT5005 scanner (20-sec data acquisition mode, bolus covering the head). The data can be summarized by the linear relations Dt = (7.5 +/- 0.8)N millirads (8 less than or equal to N less than or equal to 18) and De = (39 +/- 5)N + (1400 +/- 200)n millirads (8 less than or equal to N less than or equal to 20, 0 less than or equal to n less than or equal to 6) where Dt is the dose to the tissue anterior to the thyroid, De is the dose to the anterior tissue of the eyelid, N is the total number of CT cuts, and n is the number of cuts in which the globe of the eye is imaged.

Eye↗
PubMed1977

Therapeutic embolization for intractable chronic bleeding.

Intractable, chronic vaginal and/or vesicle bleeding complicating pelvic cancers in five women was treated by transcatheter embolization of the hypogastric artery or its branches. Bleeding was presumed to be from hypervascular granulation tissue formed in response to irradiation in two patients and from tumor tissue in three. The embolic materials were Gelfoam and Oxycel reinforced autologous clots. Bleeding was stopped or reduced in volume by at least 90% in each patient. This form of therapy was useful even though bleeding site was not demonstrated angiographically.

Chronic Disease↗
PubMedDate not supplied

Digital radiography: utilization of a nuclear medicine computer system.

A standard nuclear medicine computer system was modified to accept video input and utilized to perform digital intravenous and intra-arterial angiography, substration of CT images and enhance ultrasound images as well as to read video and magnetic tape. This system provides greater versatility and adaptability than presently conceptualized and produced digital systems and deserves further evaluation as a multipurpose imaging device.

Angiography↗
PubMedDate not supplied

Epinephrine fraction of adrenal vein blood in pheochromocytoma.

Variability in the levels of epinephrine (E) and norepinephrine (NE) in adrenal vein blood is thought to preclude their usefulness in caval sampling studies for localizing abdominal pheochromocytoma. In this study we demonstrate, in three patients, that the fraction of the total catecholamine level in the adrenal effluent represented by E (E fraction) may differentiate the normal adrenal medulla from the gland containing a pheochromocytoma. This observation is additionally supported by calculations of the E fractions, from adrenal venous E and NE reported recently, in three other patients with pheochromocytoma. Our data, combined with those from the literature, yield a mean E fraction, in adrenal vein blood, of 63.8 +/- 11.4 (SD)% for seven normal adrenal medullae, and of 28.5 +/- 4.8% for five glands bearing pheochromocytoma. The use of this parameter for lateralizing adrenal pheochromocytoma is suggested if other procedures are unable to demonstrate the tumor.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

Captopril stimulation of differential renins in renovascular hypertension.

Twenty-six patients being evaluated for renovascular hypertension were studied to assess the diagnostic value of enhancing the differential between renal venous renins (PRA) by a single 25 mg oral dose of converting enzyme inhibitor (CEI, captopril). Antihypertensive medications were not discontinued prior to the study, and renal venous effluent was sampled before and 30 minutes after CEI. Eight patients without stenosis who did not have surgery had post-CEI ratios of less than 3.0. The other 18 patients had operative intervention, with 14 subsequently having improved blood pressure control. Of these 14, seven patients with unilateral stenosis, four patients with bilateral stenosis, and one patient without overt stenosis but with other evidence of reduced renal blood flow had 30-minute PRA ratios of 3.0 or greater. Five of these 14 patients had prestimulation ratios of less than 1.5 and might not be considered operative candidates by conventional criteria. Four other patients unimproved by surgery had post-CEI ratios of less than 3.0 despite a baseline ratio of greater than 1.5 in two of four. Only two patients with post-CEI ratios of less than 3.0 were improved with surgery. We conclude that a 30-minute post-CEI renal venous ratio of 3.0 or greater enhances the probability that patients with renovascular disease, and hypertension will respond to surgical intervention with improved blood pressure control.

Adolescent↗