Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.2.1.1 (ACS)
 78,556 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the interests of uniformly high radiological physics standards at ACS-NCI Breast Cancer Detection Demonstration Projects, measurements were made at 29 breast cancer screening clinics. These measurements were made throughout the country with equipment calibrated with standards traceable to National Bureau of Standards. Histograms which indicate the frequency distribution of exposures to the surface of a 6 cm breast for various machine/receptor combinations were prepared.
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PMID:Interim report: mammographic exposures at the breast cancer detection demonstration project screening centers. 18 50

Radical mastectomy as originally conceived at the turn of the century consisted of complete removal of the breast tissue, the overlying skin, the pectoral muscles, the intervening lymphatics and the axillary lymph nodes. The aim was logical but initially the results were poor. Only 41% of the 76 patients in Halsted's original series were without disease at the end of 3 years. The principal reason for this was the advanced stage of disease in the patients selected for treatment. By contrast, Gilbertsen, using clinical examination alone, surveyed women 45 years of age or older and found that of 32 patients with breast cancers detected by the screening procedure, 24 had no axillary lymph node involvement. The absolute 5-year survival rate of this group was 96%, which approaches the anticipated survival of comparable women free of breast cancer. Those with positive lymph nodes had an absolute survival rate of 75% at 5 years. Further, of 13 patients observed for 10 years, the survival rate for those without node involvement was 90% and for patients with node involvement was 33%. Patients treated at the Barnes Hospital in St. Louis between 1912 and 1933 were contrasted with similarly treated patients at the Barnes Hospital and the Ellis Fischel Cancer Hospital from 1940 to 1955. A poorer survival rate in the earlier series was related primarily to the greater frequency of advanced and larger tumors. That a significant reduction in breast cancer mortality can be achieved is becoming increasingly apparent. Among survey-detected breast cancers in the study conducted by the Health Insurance Plan of Greater New York, the 6-year mortality was half of that of controls. This reduction is even more impressive when one considers that among these patients were many with full invasive, mass-forming carcinomas at the time of initial screening. A recent report by Wanebo, Huvos and Urban discusses the treatment of prognostically favorable forms of breast cancer by modified radical mastectomy. It is possible to select from among their patients those who fit the definition of minimal breast cancer. In this group the 5-year survival rate was 97% and the 10-year survival rate was 95%. Only 1 patient died of breast cancer in 10 years. In another reported group of 65 patients with intraductal carcinoma only, there were no deaths due to breast cancer in 10 years. Should the NCI-ACS demonstration projects show, as now seems probable, that community screening programs can be effective in early breast cnacer detection, it is to be anticipated that widespread public demand for screening facilities will follow. This may present insurmountable logistic and economic problems. The total number of radiologists in the United States is not sufficient to screen annually the total population of women over age 40, or even over age 50. There is great need for the development of criteria for the ready identification of that segment of the population in which most of the cancers would be found...
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PMID:The detection and diagnosis of early, occult and minimal breast cancer. 18 91

Purple sulfur (Ectothiorhodospira shaposhnikovii, Chromatium minutissimum, Lamprobacter modestohalophilus, Thiocapsa roseopersicina) and nonsulfur (Rhodospirillum rubrum, Rhodopseudomonas palustris, Rhodopseudomonas spheroides) bacteria are capable of forming acetyl-CoA synthetase, phosphotransacetylase and acetokinase independent of the medium composition and growth conditions. In all of the purple sulfur bacteria with an exception of E. shaposhnikovii, the activity of acetokinase is much higher than in purple nonsulfur bacteria. Apart from being involved in the synthesis of acetyl-CoA, such enzymes as phosphotransacetylase, acetokinase and adenylate kinase may play an important role in energy processes of some purple bacteria in the dark.
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PMID:[Possible pathways for acetyl-CoA formation by purple bacteria]. 22 68

In light/dark synchronized cultures of Euglena gracilis Klebs Z the enzymes malate synthase, isocitrate lyase and acetate thiokinase were induced upon addition of acetate at all stages of the cell cycle. Cycloheximide and p-fluorophenylalanine inhibited the development of enzyme activity, showing that induction was dependent on protein synthesis. The maximum rate of induction for all three enzymes was constant for much of the cell cycle but doubles in a single step during the period of DNA replication. Although these data indicate that enzyme potential was regulated by gene dosage and that the structural gene for each enzyme was continuously available for transcription during the cell-cycle it was not possible by using inhibitors of RNA synthesis, to demonstrate concurrent transcription during enzyme induction.
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PMID:Induction potential for glyoxylate cycle enzymes during the cell cycle of Euglena gracilis. 24 Jul

Of 1,810 breast cancers detected in the NCI/ACS Breast Cancer Detection Demonstration Projects, 592 were less than 1 cm in diameter and considered minimal; and tissue slides from 506 of them were available for retrospective review by a panel of pathologists. The initial report of this review indicated that in 66 cases the pathologic features of the presented slides were not sufficient for diagnosis of cancer. Subsequent investigation revealed that, through computer error, the slides submitted in 2 of these 66 cases were not from the lesions in question but from blind biopsy of the contralateral breast. Further review by the pathology panel of tissue from 38 of the 64 remaining cases determined that 16 of the remaining lesions were indeed cancers or borderline malignant lesions. This then left 48 cases in doubt. Only biopsy had been performed in 11 of them, and some form of mastectomy in the other 37. The original pathologic opinion had been divided in 30 of these, and the mastectomy had been delayed for 1 day to 7 months after the biopsy. In only 7 of the 48 questionable cases was definitive treatment carried out at the time of biopsy. All in all, these findings reflect sound, responsible surgical judgment.
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PMID:Diagnosis of minimal breast cancers in the BCDDP: the 66 questionable cases. 42 26

In order to evaluate the usefulness of thallium-201 (201TI) myocardial scintigraphy in delineating the location and size of prior myocardial infarction, 32 patients were evaluated at a mean of 7 +/- 2 months after infarction with a 12-lead ECG, resting 201TI myocardial scintigram, biplane left ventriculogram and coronary angiograms. From the left ventriculogram, asynergy was quantified as percent abnormally contracting segment (% ACS), the percent of end-diastolic circumference which was either akinetic or dyskinetic. Using a computerized planimetry system, we expressed 201TI perfusion defects as a percentage of total potential thallium uptake. Of 21 patients with ECG evidence of prior transmural infarction, a 201TI defect was present in 20 (95%), and angiographic asynergy was present in all 21 (100%). The site of prior infarction by ECG agreed with the 201TI defect location in 24 of 32 patients (75%) and with site of angiographic asynergy in 23 of 32 patients (72%). Scintigraphic defects were present in only four of 10 patients (40%) with ACS less than or equal to 6%, but scintigraphic defects were found in 20 to 22 patients (91%) with ACS greater than 6% (p less than 0.01). Thallium defect size correlated marginally with angiographic left ventricular ejection fraction (r = -0.60) but correlated closely with angiographic % ACS (r = 0.80). Thallium defect size was similar among patients with one-, two-, or three-vessel coronary artery disease (greater than or equal to 70% stenosis), but thallium defect size was larger in patients with electrocardiographic evidence of transmural infarction (p less than 0.01) or pulmonary capillary wedge pressure greater than 12 mm Hg (p less than 0.001). Thus, resting 201TI myocardial scingigraphy is useful in localizing and quantifying the extent of prior myocardial infarction, but is insensitive to small infarcts (ACS less than 6%).
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PMID:Usefulness and limitations of thallium-201 myocardial scintigraphy in delineating location and size of prior myocardial infarction. 42 82

The relationship of segmental left ventricular (LV) wall motion abnormalities to LV function 2-6 days after acute transmural myocardial infarction (MI) was investigated in 45 patients by quantitative contrast ventriculography. Patients were divided into four classes according to the MIRU criteria. Segmental wall motion was assessed by determining the percentage of systolic shortening (deltaS) along nine hemiaxes and the extent of akinetic or dyskinetic abnormally contracting segments (% ACS) expressed as a percentage of end-diastolic perimeter. When compared with that in 17 normal control-subjects, the LV end-diastolic volume was increased only in patients in class III and class IV; the LV end-systolic volume increased progressively from normal through class IV. Ejection fraction had a negative linear correlation with %ACS (r = 0.97). The size of ACS was larger in anterior (34 +/- 14%) than in inferior MIs (23 +/- 7%), resulting in greater LV dysfunction. However, for a comparable size of ACS, infarct location alone did not influence LV function parameters. In the noninfarcted zone, deltaS was increased when the size of ACS was less than 25% and reduced when the size of ACS was greater than 25%. Thus, the size of ACS is a major determinant of LV dysfunction in acute MI. The compensatory mechanisms operate either through an augmented mechanical function of residual myocardium when the infarct is small, or through the Frank-Starling mechanism when the infarct is large.
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PMID:Regional left ventricular function assessed by contrast angiography in acute myocardial infarction. 44 15

The synthesis of a new coenzyme A analogue, N6-[N-(6-aminohexyl)carbamoylmethyl]-CoA, suitable for immobilisation through its terminal amino group to support matrices, is described. The synthetic route starts with bis(CoA) and involves the following steps: alkylation with iodoacetic acid and rearrangement yielding bis(N6-carboxymethyl-CoA), elongation of the carboxymethyl terminal with 1,6-diaminohexane using carbodiimide to yield bis(N6-[N-(6-aminohexyl)-carbamoylmethyl]-CoA) and finally the splitting of this bis[CoA analogue) through reduction with dithiothreitol to give the final product in approximately 10% overall yield. This CoA analogue showed 'coenzymic activity' with the enzymes acetyl-CoA synthetase, phosphotransacetylase and succinic thiokinase. Covalent binding of the CoA analogue to Sepharose 4B was normally carried out using its S-(5-thio-2-nitrobenzoic acid) derivative as this allows a convenient way for determining the amount of ligand coupled, based on the amount of 5-thio-2-nitrobenzoic acid liberated from the gel after reduction with dithiothreitol. After covalent binding of the CoA analogue to water-soluble activated dextran 70, the analogue was recycled while present in an ultrafiltration cell using the enzymes phosphotransacetylase and citrate synthase. The reaction was followed by measuring the citrate formed on addition of acetylphosphate and oxaloacetate. In affinity chromatographic studies it was shown that the CoA-Sepharose preparation could bind the CoA-dependent enzymes citrate synthase and succinic thiokinase and these could be biospecifically eluted using soluble CoA.
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PMID:N6-[N-(6-Aminohexyl)carbamoylmethyl]-coenzyme A. Synthesis and application in affinity chromatography and as an immobilized active coenzyme. 57 88

Thirteen chromosomal loci have been identified which affect acetate metabolism in Coprinus. Mutants at only two loci, acu-l and acu-7, are deficient in isocitrate lyase (ICL) (EC 4.1.3.1) activity. acu-1 mutants are unable to induce ICL because they lack acetyl-CoA synthetase which is required to convert acetate to the metabolic inducer of ICL. acu-7 is the structural gene for ICL. This was shown by selecting temperature sensitive acu+ revertants resulting from a second mutation within the acu-7 gene. One such revertant was shown to produce an ICL protein which was more thermolabile than the wild type enzyme. Other workers have postulated that ICL activity is important during asexual morphogenesis in fungi. No evidence was found for this in Coprinus. The morphological mutant oidial, which produces abundant asexual spores even in submerged culture, had the same low uninduced level of ICL activity as the wild type. Moreover, an acu-7 mutation had no effect on the expression of the oidial phenotype.
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PMID:Genetics and function of isocitrate lyase in Coprinus. 60 Feb 68

An experimental study has been made of both the steady-state and the transient-phase (presteady-state) kinetics of the hydrolyses of several saturated aliphatic esters of p-nitrophenol catalyzed by wheat germ lipase. The analysis of the presteady- 1 Presented in part at the 173rd ACS National Meeting, New Orleans, L.A., U.S.A., March 20--25, 1977. 2 Correspondence should be addressed to M.H. Sadar, E.S.D., E.H.C., Health and Welfare Canada, Tunney's Pasture, Ottawa, Ontario, Canada, K1A OL2. 3 Department of Chemistry, University of Ottawa, Ottawa, Ontario, Canada. state part revealed two transients indicating that lipase-catalyzed reactions proceed via a two-intermediate mechanism suggested for other esterases. The possibility of more than one species of the enzyme engaged in catalytic activity is discussed and a reaction mechanism scheme is proposed accordingly.
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PMID:Transient-phase and steady-state kinetics of lipase-catalyzed ester hydrolysis. 64 7


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