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Biomedical subjects

C E Green

Publications and source records attributed to C E Green.

88 records · Page 5Linked to original sources
PubMed1980

A renewed role for fluoroscopy in the evaluation of cardiac disease.

The advent of surgical therapy for ischemic heart disease and the prospects for modification of risk factors for coronary artery disease have made the detection of coronary artery disease in asymptomatic patients more important. Cardiac fluoroscopy is an inexpensive and relatively efficacious screening method for coronary artery disease. The combination of fluoroscopy and exercise stress testing is particularly promising. Cardiac fluoroscopy also retains a place in the diagnosis of valvular heart disease. For all of the reasons listed above, we strongly recommend that cardiac fluoroscopy be performed as part of the initial evaluation of any patient suspected of having heart disease. Furthermore, when coronary calcification is discovered incidentally by the radiologist, the patient and his physician should be alerted to its presence as it represents a significant risk factor for the subsequent development of symptomatic coronary artery disease.

Aortic Valve↗
PubMed1980

Non-lymphoreticular cancer of the gastrointestinal tract in the young adult: general hospital experience.

A review of 39 cases of non-lymphoreticular cancer of the gastrointestinal (GI) tract in young adults (ages 18-40 years) compiled from the tumor registries of three general teaching hospitals during the years 1966-1976 is presented. Several aspects of their clinical presentation, diagnostic evaluation, and treatment are assessed. Several features are worthy of comment regarding this subgroup of cancer patients: unexplained anemia, evidence of GI tract blood loss, and weight loss are frequent findings, singly or in combination; delay in diagnosis of gastric malignancy may be occasioned due to response of abdominal complaints to nonspecific therapy such as antacids; and an unexpectedly high number of women were among the cancer group, especially among those with stomach and colorectal cancer.

Adenocarcinoma↗
PubMed1977

Inheritance of selected pathotoxin resistance in maize plants regenerated from cell cultures.

Texas male-sterile cytoplasm (cms-T) maize is susceptible to Helminthosporium maydis race T and its pathotoxin, whereas nonsterile cytoplasm maize is resistant. Callus cultures initiated from immature embryos of a cms-T genotype, BC(1)A188(T), were susceptible to the toxin and were capable of plant regeneration. Toxin-resistant cell lines were selected by a sublethal enrichment procedure in which cms-T callus was grown for several selection cycles (subculture transfers) in the presence of progressively higher concentrations of toxin. Periodically during the selection process, plants were regenerated from the cms-T cultures to determine their susceptibility or resistance to the toxin. Plants regenerated after four cycles of selection were male-sterile and toxin-susceptible as shown by leaf bioassays. All plants regenerated from cell lines isolated from the fifth selection cycle onward, however, were toxin-resistant and 52 of 65 were fully male-fertile. The remaining 13 "male-sterile" resistant plants did not shed pollen and did not resemble cms-T plants in tassel morphology. Some "male-sterile" plants produced anthers containing a small amount of starch-filled pollen, suggesting that the sterility of these 13 plants was not the result of the cms-T trait. Leaf bioassays on F(1) progeny from regenerated resistant plants indicated that resistance to the toxin was inherited only through the female. The male-fertility trait also was inherited only through the female. After inoculation with H. maydis race T spores, leaf lesion size for progeny from regenerated resistant plants coincided with their reaction to the toxin. This result indicated that plant resistance to the pathogen was closely correlated with the toxin resistance obtained through cell culture selection.

Journal Article↗
PubMed1975

Recovery of polysome function of T4-infected Escherichia coli after brief treatment with chloramphenicol and rifampin.

T4-infected Escherichia coli cells briefly exposed to rifampin, or to rifampin plus chloramphenicol, were capable of protein synthesis for some time after removal of the antibiotics, although ribonucleic acid synthesis was irreversibly inhibited. Partially completed peptides trapped on polysomes by high levels of chloramphenicol were eventually completed after removal of the drug, as demonstrated by subjecting labeled peptides from appropriate polysome regions to polyacrylamide disc gel electrophoresis. Thus, the effect of the drug appears to be reversible on the molecular as well as the cellular level.

Chloramphenicol↗
PubMedDate not supplied

Structure-activity relationship for the intrinsic hepatotoxicity of dinitrotoluenes.

The relation of various structural parameters to hepatotoxic potential was investigated by using six dinitrotoluene (DNT) isomers and isolated rat hepatocyte suspensions as the biological test system. DNT-induced hepatotoxicity was found to correlate with an inhibition of protein synthesis and an increase in lactate dehydrogenase (LDH) release but not with lipid peroxidation. With each isomer, protein synthesis inhibition was the most sensitive indicator of cytotoxicity. Regardless of the indicator, ortho- and para-substituted isomers were more hepatotoxic at the same concentration than meta-substituted isomers. High-performance liquid chromatograms (HPLC) on samples at 4 h revealed significant quantities of reduced metabolites in the medium. However, increased lipid peroxidation (formation of thiobarbituric acid reactants or evolution of ethane) in the cells was not consistently demonstrated. log EC50 for protein synthesis inhibition and log EC20 for LDH release were linearly correlated with the C atomic charge on the ring carbons bearing the nitro substituents by using molecular orbital (MNDO calculations) theory. The relation was used to predict the hepatotoxic potentials of untested nitrotoluenes, and the predictions were verified to a first approximation by using three trinitrotoluene isomers.

Animals↗
PubMedDate not supplied

Renal infarction with absolute ethanol.

Selective renal artery catheterization was undertaken in a series of mongrel dogs. Absolute ethanol was injected on a dose/weight ratio. Venous blood ethanol levels were monitored. Pre- and postprocedure angiography was performed to evaluate the effectiveness of the injection. The dogs were subsequently sacrificed and pathologic examination performed. Renal infarction was produced in all animals. Systemic blood alcohol levels remained consistently below established criteria of toxic levels. No evidence of vascular damage in systemic arteries distal to the renal artery was found. Absolute ethanol is apparently a safe and effective method of producing permanent renal infarction.

Animals↗
PubMedDate not supplied

Cardiovascular effects of protamine sulfate.

Rapid administration of protamine sulfate after arteriography or cardiopulmonary bypass has occasionally been associated with marked hypotension. Since it is unclear whether this is due entirely to vasodilatation or to myocardial depression in addition to vasodilatation, the authors assessed the direct myocardial and systemic circulatory effects of this drug in seven anesthetized dogs. Direct effects of protamine sulfate on global and regional myocardial function and peripheral arterial resistance were determined in the presence and absence of segmental myocardial ischemia. Effects on the myocardium were determined by intracoronary administration of protamine; effects on the systemic circulation were determined after intravenous administration. Intracoronary administration of protamine caused no significant change in left ventricular contractility in either the normal or ischemic state. Intravenous administration produced hypotension due to peripheral vasodilation.

Animals↗
PubMedDate not supplied

Physiologic--angiographic correlates of coronary arterial stenoses in resting and intensely vasodilated states.

The treatment of ischemic heart disease is dependent upon defining the physiologic significance of coronary arterial stenoses demonstrated on coronary arteriograms. Accordingly, physiologic--angiographic correlates were studied in 12 anesthetized dogs prepared with an electromagnetic flowmeter and micrometer-controlled occluder on the circumflex coronary artery, a pair of sonic crystals in the myocardium within the distribution of the circumflex artery, and a catheter in the thoracic aorta. Measurement of arterial diameters on coronary arteriograms was made to define the minimum percent stenosis that caused: (1) decrease in resting coronary blood flow (CBFr); decline in the peak level of coronary blood flow (CBF) produced by intense vasodilatation induced by intracoronary infusion of ATP (CBFATP); and (3) segmental left ventricular (LV) dysfunction. CBFR decreased at an average stenosis of 80.45 +/- 9.13% (SD) (percent reduction in luminal diameter), while CBFATP declined at a stenosis of 31.83 +/- 5.64%. Segmental LV dysfunction was observed at a stenosis of 85.92 +/- 9.83%. In all dogs, the initial stenosis causing decline in CBFATP was a less than or equal to 40% reduction in luminal diameter. The results of this study indicate that coronary arterial stenoses of 40% or less may be hemodynamically significant under situations of augmented CBF. On the other hand, regional contractile function at rest is preserved up to stenosis in excess of 80%.

Adenosine Triphosphate↗
PubMedDate not supplied

Primary cardiac and pericardial neoplasms: radiologic-pathologic correlation.

Primary cardiac and pericardial neoplasms are rare lesions and include both benign and malignant histologic types. Myxoma is the most frequent primary cardiac neoplasm, but other benign tumors include papillary fibroelastoma, rhabdomyoma, fibroma, hemangioma, lipoma, and paraganglioma. Cardiac sarcoma represents the second most common primary cardiac neoplasm. Lymphoma can also affect the heart primarily. Pericardial tumors that affect the heart include benign teratomas and malignant mesotheliomas. Patients affected with cardiac or pericardial neoplasms often present with cardiovascular compromise or embolic phenomena and exhibit cardiomegaly at chest radiography. Benign cardiac tumors typically manifest as intracavitary, mural, or epicardial focal masses, whereas malignant tumors demonstrate invasive features and may involve the heart diffusely. Benign lesions can usually be successfully excised, but patients with malignant lesions have an extremely poor prognosis.

Diagnostic Imaging↗
PubMedDate not supplied

Polymorphic N-acetylation of sulfamethazine and benzidine by human liver: implication for cancer risk?

Extensive epidemiologic studies have indicated a relationship between bladder cancer in populations exposed to arylamines and the slow phenotype for acetylation of arylamines (e.g., sulfamethazine) and aryl hydrazides (e.g., isoniazid). In human liver preparations, we have examined the association between the capability for sulfamethazine acetylation and that for the human bladder arylamine carcinogen, benzidine. By the usual criteria for polymorphic acetylation, we classified the 10 donor subjects as four rapid and six slow acetylators of sulfamethazine. Concurrent tests of benzidine acetylation in the same liver preparations yielded capacities to acetylate benzidine that were directly and significantly correlated with those for sulfamethazine acetylation (r = 0.672; P less than 0.05). We suggest that acetylation of these two compounds is directly related and knowledge of the human acetylator phenotype may be a useful indicator of possible risk for bladder cancer due to exposure of certain arylamines and, perhaps for other cancers in man.

Acetylation↗
PubMedDate not supplied

Comparative metabolism of tolbutamide by isolated hepatocytes from rat, rabbit, dog, and squirrel monkey.

Tolbutamide (TB; 1-butyl-3-p-tolylsulfonylurea) was used for metabolism studies with hepatocytes isolated from the rat, rabbit, dog, and squirrel monkey to validate their usefulness as models for comparative in vivo metabolism. Hepatocytes were prepared by whole liver or biopsy perfusion. TB (3 X 10(-4) M) was metabolized by each of the preparations over a 4-hr incubation period at rates ranging from 175.8 to 9.2 pmol/10(6) cells/min with the rates from hepatocytes from: rat greater than rabbit much greater than squirrel monkey greater than dog. The metabolite profiles determined in extracts of hepatocyte suspensions after 4 hr of incubation showed marked species differences. The major metabolite for the rat and squirrel monkey was 1-butyl-3-p-hydroxy-methylphenylsulfonylurea (73.2 and 46.7% of total metabolites, respectively). p-Tolylsulfonylurea and p-tolylsulfonamide were the major metabolites found in the dog (44.1 and 40.2%, respectively). Rabbit hepatocytes formed mostly 1-butyl-3-p-carboxyphenylsulfonylurea (63.9%). Both the relative rates of metabolism and the metabolite profiles from hepatocytes from the rat, rabbit, and dog correlated well with published in vivo data on TB plasma half-lives and urinary metabolite profiles. These results suggest that isolated hepatocytes may have utility as in vitro models for comparative in vivo metabolism.

Animals↗