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Biomedical subjects

J H Phillips

Publications and source records attributed to J H Phillips.

At least 217 records · Page 12Linked to original sources
PubMed1981

Coronary angiography post first myocardial infarction in the asymptomatic or mildly symptomatic patient: clinical, angiographic, and prospective observations.

The role of coronary arteriography in the asymptomatic or mildly symptomatic post first myocardial infarction patient is controversial. Thirty-one class 0-1 patients (Canadian Heart Association Grading System) underwent coronary arteriography within six months (mean 67 days) of their first myocardial infarction. Coronary arteriography revealed three-vessel disease in nine (29%), two-vessel disease in ten (32%), single-vessel disease in ten (32%), and normal coronary arteries in two (6%). No patient had left main disease, and two (6%) had left main equivalent disease. In 12 patients with single-vessel disease or normal coronary arteries there were no morbid events over a mean follow-up period of 26 months. In the 19 with multivessel disease, eight (40)% developed a cardiac event during a mean follow-up period of 11.4 months. These included one who elected to undergo immediate aortocoronary bypass surgery, two with unstable angina, three acute myocardial infarctions, and two deaths. Based on these data and review of the literature, a scheme is proposed for the subsequent evaluation and treatment of this patient group.

Adult↗
PubMed1981

Early treadmill testing and coronary arteriography after myocardial infarction.

Thirteen male patients underwent early symptom-limited treadmill testing and coronary arteriography after their first myocardial infarction. All were functional class I at the time of evaluation, and none sustained any complications. Of five patients with a negative treadmill test, two had single-vessel disease, one had double-vessel disease, and two had triple-vessel disease. Two had elective aortocoronary bypass surgery, and three remained asymptomatic during a one-year follow-up. Eight patients had a positive test. From this group, one had single-vessel disease, one had double-vessel disease, and six had triple-vessel disease, including two with stenosis of the left main coronary artery. Four had aortocoronary bypass surgery, two died suddenly, progressive angina developed in one, and one remained asymptomatic. Early treadmill testing and coronary angiography in asymptomatic survivors of their first myocardial infarction is safe and extremely valuable in identifying patients with critical multivessel coronary artery disease.

Adult↗
PubMed1981

Coronary artery spasm: a mechanism of chest pain in selected patients with the mitral valve prolapse syndrome.

A group of 14 patients with mitral valve prolapse syndrome was referred for coronary angiographic study. The group was selected on the basis that all members had recurrent chest pain as their chief complaint and all had interpreted their chest pain as serious enough to warrant at lest two previous emergency visits to medical facilities in the six months preceding the study. All were found to have normal left ventricular function, and only one had a significant fixed obstructive coronary lesion. Seven of 14 patients (50 percent) showed evidence of coronary artery spasm during the catheterization study, five of whom had histories highly suggestive of coronary vasospasm. During the catheterization, spasm occurred spontaneously in three patients, ws ergonovine-induced in two, and was catheter-tip-induced in two. Ergonovine was administered to nine of the 14 patients. The drug induced vasospasm in two patients but failed in seven (two of whom had previously demonstrated catheter tip spasm). Of those seven patients who showed evidence of spasm, four had typical chest pain in association with reversible ST segment elevation and manifested a variant anginal syndrome.

Adult↗
PubMed1981

[Not Available].

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History of Medicine↗
PubMed1981

Tuftsin: a naturally occurring immunopotentiating factor. I. In vitro enhancement of murine natural cell-mediated cytotoxicity.

Tuftsin is a physiologic tetrapeptide, which has recently been shown to possess immunoadjuvant properties including the stimulation of macrophage and granulocyte phagocytosis, migration, bactericidal, and tumoricidal activities. Tuftsin has also been reported to possess in vivo immunologically mediated anti-tumor potential. To determine the potential role of tuftsin as an antineoplastic immunoadjuvant, the in vitro effects of tuftsin on murine natural cell-mediated cytotoxicity were studied. We observed that in vitro treatment of mouse splenic effector cells with synthetic tuftsin induced a pronounced enhancement of natural killer cell (NKC) cytotoxicity against the T cell lymphoma Yac-1. The magnitude of NKC enhancement was directly dependent upon the concentration of tuftsin employed, with maximum NKC stimulation observed at tuftsin concentrations of 50 to 100 microgram/ml. The tuftsin induced enhancement of NKC activity was not strain specific, since equivalent stimulation was seen in CBA/J, C56BL/10, and DBA/2 mice. Elimination of macrophages, monocytes, T cells, and immunoglobulin-bearing cells had no effect on the dose-dependent tuftsin stimulation of natural cell-mediated cytotoxicity; thus the characteristics of the effector cells activated by tuftsin were consistent with those reported for NKC. We also observed that treatment of splenic effector cells with tuftsin prolonged the cytotoxic capabilities of these cells beyond 18 hr.

Adjuvants, Immunologic↗
PubMed1980

Stoichiometry of catecholamine/proton exchange across the chromaffin-granule membrane.

Catecholamines are accumulated by bovine chromaffin-granule "ghosts" in the presence of MgATP at 25 degrees C. With low concentrations of catecholamine, ratios of internal to external amine concentration of up to 20 000 were obtained. These values fit well with a transport model in which amine accumulation is both electrogenic and dependent on a pH gradient across the membrane.

Animals↗
PubMed1980

Inhibition of adenosine triphosphatase, 5-hydroxytryptamine transport and proton-translocation activities of resealed chromaffin-granule 'ghosts'.

1. Highly purified resealed chromaffin-granule ;ghosts' were assayed for ATPase and ATP-driven H(+)-translocation and 5-hydroxytryptamine-uptake activities, and for 5-hydroxytryptamine uptake driven by an imposed transmembrane H(+)-gradient. The effects of several inhibitors on these activities were studied. 2. Dicyclohexylcarbodi-imide inhibits all of these activities, but not in parallel; at low concentrations it decreases the permeability of the membrane to protons. 3. 4-Chloro-7-nitrobenzofuran (Nbf-Cl) and silicotungstate inhibit ATP-dependent activities, without effect on 5-hydroxytryptamine uptake driven by an imposed H(+)-gradient. 4. Tributyltin chloride inhibits all of the activities. 5. Treatment of the ;ghosts' with low concentrations of urea inhibits 5-hydroxytryptamine uptake and ATP-dependent generation of a transmembrane H(+)-gradient, without inhibiting ATPase activity. 6. Nbf-Cl and silicotungstate are without effect on the rate of leakage of 5-hydroxytryptamine from preloaded ;ghosts', whereas dicyclohexylcarbodi-imide and tributyltin chloride accelerate the rate of leakage. 7. Treatment of the membranes with (14)C-labelled Nbf-Cl labels several proteins; membranes treated with dicyclohexyl[(14)C]carbodi-imide are labelled predominantly in a protein of low molecular weight, which may be analogous to the mitochondrial H(+)-conducting proteolipid. 8. It is concluded that Nbf-Cl and silicotungstate inhibit the H(+)-translocating ATPase of the granule membrane; that dicyclohexylcarbodi-imide inhibits the ATPase, and inhibits 5-hydroxytryptamine accumulation by accelerating leakage of the amine; and that the effects of tributyltin chloride are due to inhibition of the ATPase, and collapse of the transmembrane H(+)-gradient through OH(-)-anion exchange.

Adenosine Triphosphatases↗
PubMed1980

Organisation of the proteins of the chromaffin granule membrane.

The organisation of the protein components of bovine chromaffin granules has been investigated by labelling or digesting intact granules or broken membranes with the following reagents: lactoperoxidase/Na125I as a reagent for tyrosine residues, N-(iodoacetylaminoethyl)-5-naphthylamine-1-sulphonic acid as a reagent for cysteine residues, pronase, and galactose oxidase/KB3H4. Following treatment, membranes were purified and washed and proteins were examined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate. Rather more than 60 bands were resoved, of which about 40 were relatively intense and reproducible. The bands were classified according to their molecular weights and sensitivity to reagents. Penetration of the membranes by the reagents was assessed by examination of intragranular porteins. The majority of chromaffin granule membrane polypeptides became labelled when intact granules were treated with impermeant reagents. Eleven were probably protected in the intact granules, reactive sites becoming exposed only on membrane lysis. By contrast, carbohydrate moieties of glycoproteins appear to be exposed only on the matrix side of the membrane. Two proteins were shown to span the membrane, although this is probably an underestimate.

Adrenal Medulla↗
PubMed1980

Atrioventricular and intraventricular conduction disturbances in aortic valvular disease.

Electrophysiologic studies of His' bundle were done on 32 consecutive patients with symptomatic aortic valvular disease. Nineteen had pure aortic regurgitation and 13 had aortic stenosis, four with significant regurgitation. Fifteen of the former had atrioventricular (AV) and/or intraventricular (IV) conduction abnormalities. In those with aortic stenosis, eight had conduction abnormalities, all intraventricular but one. Twelve of the 13 with aortic stenosis had radiographically indentifiable valve calcification; all four with a peak systolic gradient greater than 80 mm Hg had IV conduction defects. Of the 32 patients, six had A-H prolongation and in all the predominant lesion was aortic regurgitation (one with moderate stenosis). There was no difference in age, clinical congestive heart failure, coronary artery disease, or prolonged H-V interval. However, PR prolongation (P = .01) and decreased ejection fraction (P = .02) was significantly increased in the former group. Patients with aortic regurgitation had longer A-H and H-V intervals (NS), induced A-V block at lower heart rates (P = .01), and higher A-V node effective (P = .001) and functional (P = .01) refractory periods. In summary, patients with aortic valvular disease have a high incidence of atrioventricular and intraventricular conduction disease.

Adult↗
PubMed1980

Chronic ventricular dysrhythmia in the mitral valve prolapse syndrome: frequency and clinical significance of ventricular site of origin.

Twenty-two patients with the mitral valve prolapse-click syndrome and chronic ventricular dysrhythmia were judged to have either right or left ventricular premature contractions on the basis of electrocardiographic QRS configuration of the premature beats. The 11 patients with right-sided premature ventricular contractions (PVCs) were younger (P < .01), and had less abnormal electrocardiograms (NS) and fewer complications (NS) than those with left-sided PVCs. Coronary arteriograms performed on four in the latter group were normal, supporting a noncoronary etiology for the arrhythmia. Thus, patients with mitral valve prolapse and chronic ventricular dysrhythmia appear to have an equal prevalence of right- and left-sided premature complexes and, though not statistically significant, there was a consistent trend toward a more malignant course in the group with left ventricular premature complexes.

Adolescent↗
PubMed1980

Coronary ostial stenosis.

Coronary ostial stenosis as a complication of atherosclerosis is a rarely emphasized angiographic finding. Its recognition is important because of the adverse prognosis of left main stenosis and the inherent risks during catheterization of these patients. Recently 3 patients were identified with left coronary ostial stenosis. A clinical picture emerged during coronary angiography characterized by an abrupt fall in catheter tip pressure associated with symptoms of dyspnea and chest pain. Contrast media injections into the sinus of Valsalva, in right anterior oblique and left anterior oblique projections, revealed characteristic angiographic changes.

Constriction, Pathologic↗