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Biomedical subjects

C E Jones

Publications and source records attributed to C E Jones.

At least 127 records · Page 7Linked to original sources
PubMed1983

Sensitive and selective assay for adenosine using high-pressure liquid chromatography with fluorometry.

A new method for quantitation of adenosine was tested in canine myocardial extracts. The method involves incubation of the extract with chloroacetaldehyde to form the fluorescing adenosine derivative 1, N6-ethenoadenosine. The ethenoadenosine is separated by high-pressure liquid chromatography (HPLC) and quantitated by fluorometry. Experiments demonstrated that 1) the method is selective for adenosine, 2) fluorescence peak height is linearly related to the quantity of ethenoadenosine, and 3) adenosine in the extract is quantitatively converted to ethenoadenosine by the incubation procedure. Also, within the range of adenosine concentrations seen in five extracts, estimates of myocardial adenosine content with the fluorometric method were nearly identical to those using the more routine technique of HPLC with direct detection by ultraviolet (UV) absorption. A primary advantage of the fluorometric method is its greater sensitivity. As little as 0.50 pmol on the column could be quantitated by fluorescence, compared with approximately 20 pmol with UV absorption. Because of the greater sensitivity, the fluorometric method should be more easily applied to samples with smaller adenosine concentrations.

Adenine↗
PubMed1983

Renal responses of the cardiac-denervated nonhuman primate to blood volume expansion.

Experiments were performed to determine whether total, specific cardiac denervation affects the renal responses of the nonhuman primate to acute intravascular volume expansion. Adult male Macaca fascicularis monkeys underwent chronic intrapericardial cardiac denervation or sham surgery. After a 14- to 30-day recovery period, each animal was anesthetized with sodium pentobarbital and estimated blood volume was volume-expanded 20% with 6% dextran in isotonic saline. Control renal excretory function did not differ between the two groups, and both groups had similar increases in urine flow, sodium and potassium excretion, osmolar clearance, free water clearance, and renal plasma flow after volume expansion. The times to peak diuresis and natriuresis also were similar in both groups. These results demonstrate that the cardiac-denervated monkey shows unattenuated renal excretory responses to volume expansion. This could indicate that either cardiac receptors do not play a major role in eliciting these responses in the primate or that eliminating a role of cardiac afferents is compensated for by redundant afferents from arterial baroreceptors.

Animals↗
PubMed1983

Simple method for quantifying pulmonary metastases in a murine fibrosarcoma.

A simple method is described for quantitating pulmonary metastases in C57BL/6J mice implanted with the Lewis T241 fibrosarcoma. Lungs were removed from tumor-bearing mice, homogenized, and diluted to 14 ml with supplemented Roswell Park Memorial Institute Tissue Culture Medium 1640 (+5% fetal calf serum). Twenty-five microliters of lung suspension from individual mice were added to a flat-bottomed microtiter plate containing 175 microliters of supplemented media, pulsed with [3H]thymidine, and incubated for 20 hr at 37 degrees. The cells were processed with a multiple automated sample harvester and counted in a liquid scintillator. Total lung burden was extrapolated from measured radioactivity (as cpm) through the use of a standard curve. This method is reasonably accurate and precise and provides more quantitative information on the pulmonary metastatic process than most conventional assays.

Animals↗
PubMed1983

Evidence that a coronary alpha-adrenergic tone limits myocardial blood flow and oxygenation in acute hemorrhagic hypotension.

In 17 anesthetized dogs, left coronary blood flow (LCBF), left ventricular oxygen extraction [(a-v)O2], and myocardial oxygen consumption (MVO2) were monitored. Coronary perfusion pressure (CPP) was varied over a wide range by hemorrhage, and the effects of alpha-adrenergic blockade elicited by intracoronary phenoxybenzamine were assessed. During normotension (CPP greater than 80 mm Hg), blockade increased LCBF by 31 +/- 6 (SEM) %, but (a-v)O2 was substantially decreased so that MVO2 was increased by only 13 +/- 3%. At lower levels of CPP, the absolute increase in LCBF caused by blockade was similar to that during normotension, but because of the reduced preblockade LCBF, the percentage increase was greater. Thus, at a CPP of 50-80 mm Hg, LCBF increased by 41 +/- 15%, and at CPP less than 50 mm Hg, LCBF increased by 47 +/- 11% (P less than 0.05 compared to percentage of change during normotension). Furthermore, during hypotension the increase in LCBF after blockade was not accompanied by a large decrease in (a-v)O2. Consequently, in severe hypotension (CCP less than 50 mm Hg), both the absolute increase and the percentage increase in MVO2 was significantly greater than during normotension. These data suggest that during hypotension, especially severe hypotension, an alpha-adrenergic tone in the coronary circulation limits coronary flow and myocardial oxygenation.

Animals↗
PubMed1982

Inosiplex therapy in subacute sclerosing panencephalitis. A multicentre, non-randomised study in 98 patients.

Inosiplex was administered to 98 patients with subacute sclerosing panencephalitis (SSPE) in the United States and Canada for variable periods of time up to 9.5 years. Survival data from these 98 patients were compared by life-table analysis with survival in three SSPE control groups drawn from SSPE patients contracting the disease in Israel, Lebanon, or the United States at about the same time as the inosiplex-treated patients but treated differently or not at all. In the inosiplex-treated patients the actuarial probability of survival at 2, 4, 6, and 8 years from onset of SSPE was 78%, 69%, 65%, and 61%, compared with 38%, 20%, 14%, and 8% in a composite control group (p less than 0.01 for all four comparisons). Statistical adjustments for time-to-treatment bias did not affect this result: a modified logrank procedure demonstrated that the risk of dying in the treatment group was 43% of that in the controls. Inosiplex seems to be able to prolong life in patients with SSPE.

Actuarial Analysis↗
PubMed1982

Effect of aminophylline on coronary functional hyperemia and myocardial adenosine.

The role of adenosine in coronary functional hyperemia was tested using the adenosine antagonist aminophylline. In 11 dogs left coronary blood flow (LCBF) and left ventricular oxygen extraction [(a-v)O2] were monitored. Myocardial oxygen consumption (MVO2) was calculated. Before aminophylline was administered, intracoronary infusion of 6.8 micrograms/min norepinephrine increased LCBF and MVO2 by 40-80%. Simultaneous infusion of adenosine further increased LCBF. Fifteen minutes after injection of 100 mg aminophylline, norepinephrine still increased LCBF, and the ratio delta LCBF/delta MVO2 was unchanged (P greater than 0.05). Although the functional hyperemia was not blunted, the response to infused adenosine was abolished by aminophylline. In 20 additional dogs myocardial adenosine was determined. Before norepinephrine infusion myocardial adenosine with and without aminophylline was 12.7 and 14.3 nmol/g dry wt, respectively (P greater than 0.05). During norepinephrine infusion an increase in adenosine correlated well with increases in MVO2 and LCBF, but the increase in adenosine was not greater after aminophylline. Thus the failure of aminophylline to blunt functional hyperemia was not due to a higher adenosine level after aminophylline. These results do not support a role for adenosine in functional hyperemia elicited by norepinephrine.

Adenosine↗
PubMed1982

A histochemical evaluation of metabolism in the coronary vasculature of the primate.

Coronary arteries and arterioles in the left ventricle from the primate Macaca fascicularis were histochemically examined to evaluate their metabolic profiles. Succinate dehydrogenase and cytochrome oxidase activities were assessed to evaluate aerobic metabolic capacity, while myosin ATPase activity was determined as an index of ATP utilization for contraction. Anaerobic capacity was evaluated from lactate dehydrogenase and glycogen reactivity. Glucose-6-phosphate dehydrogenase was examined to determine capacity of the hexose-monophosphate-shunt, while the amounts of deoxyribonucleicc and ribonuclei acids were assessed as possible indicators of protein synthesis. Succinate dehydrogenase and cytochrome oxidase demonstrated slight reactivity in both coronary arteries and arterioles indicating a low capacity for aerobic metabolism. Myosin ATPase showed strong activity in arteries and even stronger reactivity in arterioles, suggesting that arteriolar smooth muscle is more capable of utilizing ATP. Glucose-6-phosphate dehydrogenase activity was extremely low in both arteries and arterioles, while deoxyribonucleic and ribonucleic acids demonstrated only slight to moderate reactivity in both arteries and arterioles, indicating that under normal conditions the coronary vasculature appears quite stable with little cell proliferation.

Animals↗
PubMed1982

Reduced oxygen and blood flow demands in the chronically sympathectomized heart.

Using an anesthetized, open-chest preparation, seven 3-week sympathectomized (CS) and eight 3-week sham operated (SO) dog hearts were studied. Circumflex blood flow per 100-g heart (CBF), left ventricular oxygen extraction [(a-v)O2], maximal dP/dt, and tension-time index (TTI) were measured at constant heart rate while aortic pressure (AoP) was changed by aortic constriction or hemorrhage. Left ventricular myocardial oxygen consumption (MVO2) was calculated from (a-v)O2 and CBF. The MVO2, CBF, (a-v)O2, and maximal dP/dt were related to TTI at each level of AoP by regression analyses. Over a wide range of TTI, MVO2 and CBF in CS were only about 50% of those in SO; (a-v)O2 was not different between the groups. These data indicate that the chronically sympathectomized heart operates at reduced oxygen and blood flow demands. Also, since (a-v)O2 and the regression of CBF on MVO2 were not different between the two groups, the data suggest that the reduced CBF in CS was secondary to a metabolic vasocontriction resulting from the reduced MVO2. Analyses of maximal dP/dt did not indicate that the reduced MVO2 in CS was as a result of reduced contractility.

Adrenergic Fibers↗
PubMed1981

Sequence of a phosphorylation site in nucleolar protein B23.

The sites of phosphorylation in protein B23, a silver-staining preribosomal ribonucleoprotein particle protein, were analyzed by tryptic peptide mapping. Three 32P peptides were found using in vitro labeling of nucleoli. An additional unlabeled phosphopeptide was identified by amino acid analysis. The sequence of the latter was Asp-Thr(P)-Pro-Ala-Lys. These results suggest that protein B23 contains one class of site labeled rapidly in vitro and another type of site phosphorylated only in vivo.

Adenosine Triphosphate↗
PubMed1981

Protective effect of chronic versus acute cardiac denervation on contractile force during coronary occlusion.

The effects of acute coronary artery (CA) occlusion on myocardial contractile force were studied in mongrel dogs with (1) chronically denervated hearts (n = 10), (2) acutely denervated hearts (n = 5), and (3) normally innervated hearts (n = 6). Contractile force was measured in ischemic and nonischemic areas using Walton-Brodie strain gauge arches sutured to the epicardium. Coronary occlusion was accomplished by ligating several small branches of the left anterior descending and the circumflex arteries supplying the apical region on the left ventricle. Following occlusion, contractile force in the ischemic area decreased by 66.8% in the control group, by 73.6% in the acutely denervated group, but only by 21.6% (P less than 0.001) in the chronically denervated group. These results demonstrate that chronic cardiac denervation protects from the severe loss of contractile force in the ischemic area. This salutary effect is not seen with acute cardiac denervation.

Animals↗
PubMed1981

Fluorescent enzyme immunoassay for antibody to single- or double-stranded DNA.

Fluorescent enzyme immunoassays have been developed for antibody to either single-stranded (ssDNA) or double-stranded (dsDNA) DNA. Preliminary testing of several clinically distinct groups of persons is consistent with the suggestion that the former assay (anti-ssDNA antibody) has sufficient sensitivity and specificity to be used as a generalized test for the detection of possible systemic lupus erythematosus in a heterogeneous clinical population. Further evaluation may ultimately establish its utility in the diagnosis of other related disorders. The sensitivity and specificity of the anti-dsDNA antibody fluorescent enzyme immunoassay are compatible with its use as a confirmatory test in the laboratory diagnosis of systemic lupus erythematosus. Qualitative comparisons between both assays and the more classic laboratory procedures involved in the diagnosis and treatment of systemic lupus erythematosus were quite favorable. The enzyme immunoassay method appears to be acceptably reproducible, and rheumatoid factor has neither a suppressive nor an enhancing effect on test values.

Adult↗
PubMed1981

Origin of handicap in young children.

A survey was carried out of all infants born in Southampton and South-west Hampshire Health District in 1975 to assess the incidence and cause of handicapping conditions at age 2-3 years. Twenty-four infants were identified with major handicap. A prenatal cause was identified in 15 cases, a perinatal cause in 5 cases, and a postnatal cause in 2 cases. No cause was identified in 2 cases. The incidence of cerebral palsy was 1.2 per 1000 live births. There was some evidence for a perinatal cause in half of them.

Accidents↗
PubMed1981

Evidence for increased protein synthesis in myocardial microvessels after chronic sympathectomy in the dog.

Using histochemical methods, evidence of increased protein synthesis was observed in microvessels (diameter less than 100 micrometers) from dog hearts which had been sympathectomized 2 weeks earlier when compared to controls. Such evidence consisted of increased staining intensity for the enzyme glucose-6-phosphate dehydrogenase and for the nucleic acids RNA and DNA. Increases in reaction intensities were noted in approximately 30% of the microvessels examined from the sympathectomized hearts, and may imply a vascular proliferation in these hearts. However, since no increase in capillary density was observed in sympathectomized hearts, a vascular proliferation, if it occurred, may have been involved in development of the coronary collateral circulation. These data support previous results indicating that collateral resistances are reduced following chronic cardiac sympathectomy while resistance of the coronary vascular bed itself is not altered.

Animals↗
PubMed1980

Carotid artery surgery without a temporary indwelling shunt. 1,917 consecutive procedures.

One thousand nine hundred seventeen consecutive carotid artery operations were performed in which the carotid artery was clamped for as long as necessary to accomplish a revascularization procedure. Those patients adversely affected by failure to use a shunt were identified. Results of a statistical analysis of stroke morbidity when compared with the literature show that the use of an intraoperative temporary shunt does not offer improved results in carotid artery surgery.

Adult↗
PubMed1980

The myocardium and its vasculature: a histochemical comparison of the normal and chronically sympathectomized dog heart.

Using histochemical techniques, the reactivities of selected enzymes and other metabolic components were examined in the myocardium, coronary arteries, and coronary arterioles of normal, two-week-sympathectomized, and sham-operated canine hearts. There were no differences in the histochemistry of coronary arteries in any of the hearts, but important differences were noted in the myocardium and especially in the arterioles. The reactivities of the enzyme glucose-6-phosphate dehydrogenase and the nucleic acids were increased in arterioles of the sympathectomized heart, possibly indicating an increased protein synthesis. The reactivities of succinate dehydrogenase, NAD-isocitrate dehydrogenase, and cytochrome oxidase were reduced in myocardium and arterioles of sympathectomized hearts as well as in arterioles of sham-operated hearts; the changes were greater in the sympathectomized arterioles where there was also observed an increase in reactivity of lactate dehydrogenase. These findings suggest a depression in aerobic metabolic capacity and, in the case of the sympathectomized arteriole, imply a possible shift in adaptation from aerobic to anaerobic metabolism.

Animals↗
PubMed1980

Phosphodipeptide analysis of nonhistone nuclear proteins from Novikoff hepatoma ascites cells.

To study the sites of phosphorylation in nuclear proteins a simple method was developed for the isolation and analysis of phosphodipeptides. Partial acid hydrolysates of unfractionated nonhistone nuclear proteins were subjected to Dowex-1 column chromatography followed by paper electrophoresis at pH 1.8. Phosphoserine- and phosphothreonine-containing dipeptides each had characteristic mobilities in the latter system. By subtractive Edman degradation these peptides were identified as having the general structure, X-PSer or X-PThr, where X is a nonphosphorylated amino acid. The two groups of phosphodipeptides were further purified into unique peptides by two-dimensional paper electrophoresis at pH 3.6 and 6.5. Amino acid analysis, and thus nearest neighbor analysis, of phosphodipeptides from nonhistone nuclear proteins revealed that a heterogeneous group of amino acids was on the amino terminal side of phosphoserine residues. In contrast, phosphothreonine residues were predominantly preceded by proline.

Amino Acids↗
PubMed1980

Reduced coronary collateral resistances after chronic ventricular sympathectomy.

Previous work has suggested that chronic ventricular sympathectomy causes a reduction in coronary collateral resistances. In the present experiments an isolated dog heart procedure was used to directly measure directional collateral resistances in 12 acutely denervated controls and 8 hearts that had undergone ventricular sympathectomy 2 wk earlier. In the procedure, the major coronary arteries were perfused separately but simultaneously during maximum vasodilation, and collateral resistances supplying the vascular beds of the arteries were determined by the double retrograde flow method. In the sympathectomized hearts, all collateral resistances were 47--65% less than in the controls (P less than 0.05). Also, in all hearts, minimum antegrade coronary resistances were determined from pressure-flow relationships in the major coronary arteries. Minimum coronary resistances in the 2 groups were not significantly different (P greater than 0.05). These results indicate that 2 wk of ventricular sympathectomy indeed causes a reduction in coronary collateral resistances, but has no effect on coronary resistances.

Animals↗