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Biomedical subjects

B Murray

Publications and source records attributed to B Murray.

88 records · Page 5Linked to original sources
PubMed1978

Cardiac risk factors and complications in non-cardiac surgery.

In an attempt to assess cardiac risk in non-cardiac surgery, 1001 patients over 40 years of age who underwent major operative procedures were examined preoperatively, observed through surgery, studied with at least one postoperative electrocardiogram, and followed until hospital discharge or death. Documented postoperative myocardial infarction occurred in only 18 patients; though most of these patients had some pre-existing heart disease, there were few preoperative factors which were statistically correlated with postoperative infarction. Postoperative pulmonary edema was strongly correlated with preoperative heart failure, but 21 of the 36 patients who developed pulmonary edema did not have any prior history of heart failure. Nearly all of these 21 patients were elderly, had abnormal preoperative electrocardiograms, and had intraabdominal or intrathoracic surgery. In the absence of an acute infarction, bifascicular conduction defects, with or without PR interval prolongation, never progressed to complete heart block. Spinal anesthesia protected against postoperative heart failure but not against other cardiac complication. By multivariate regression analysis, postoperative cardiac death was significantly correlated with (a) myocardial infarction in the previous 6 months; (b) third heart sound or jugular venous distention immediately preoperatively; (c) more than five premature ventricular contractions per minute documented at any time preoperatively; (d) rhythm other than sinus, or premature atrial contractions on preoperative electrocardiogram; (e) age over 70 years; (f) significant valvular aortic stenosis; (g) emergency operation; (h) a 33% or greater fall in systolic blood pressure for more than 10 minutes intraoperatively. Notably unimportant factors included smoking, glucose intolerance, hyperlipidemia, hypertension, peripheral atherosclerotic vascular disease, angina, and distant myocardial infarction.

Adult↗
PubMed1977

Multifactorial index of cardiac risk in noncardiac surgical procedures.

To determine which preoperative factors might affect the development of cardiac complications after major noncardiac operations, we prospectively studied 1001 patients over 40 years of age. By multivariate discriminant analysis, we identified nine independent significant correlates of life-threatening and fatal cardiac complications: preoperative third heart sound or jugular venous distention; myocardial infarction in the preceding six months; more than five premature ventricular contractions per minute documented at any time before operation; rhythm other than sinus or presence of premature atrial contractions on preoperative electrocardiogram; age over 70 years; intraperitoneal, intrathoracic or aortic operation; emergency operation; important valvular aortic stenosis; and poor general medical condition. Patients could be separated into four classes of significantly different risk. Ten of the 19 postoperative cardiac fatalities occurred in the 18 patients at highest risk. If validated by prospective application, the multifactorial index may allow preoperative estimation of cardiac risk independent of direct surgical risk.

Age Factors↗
PubMedDate not supplied

Behavioral measures of conduction velocity and refractory period for reward-relevant axons in the anterior LH and VTA.

Psychophysical techniques were used to estimate the conduction velocities and refractory periods of reward-relevant fibers in the anterior lateral hypothalamus (ALH) and ventral tegmental area (VTA). Six male rats of the Long-Evans strain served as subjects. Stimulation consisted of trains of pulse pairs delivered to the ALH and VTA; each stimulation site received one pulse from each pair. Collision of antidromic and orthodromic action potentials along the same reward-relevant axons was inferred from a decrease in the effectiveness of the stimulation at short intra-pair intervals. Significant collision-like effects were obtained for 5 of the 6 subjects, supporting the notion that reward-relevant neurons directly link the ALH and VTA. Estimates of the slowest conduction velocities ranged from 0.4 to 5.5 m/s. Refractory period estimates, obtained by delivering the trains of pulse pairs to a single stimulation site, ranged from 0.5 to 5.4 ms. The overlap between these psychophysical estimates and the electrophysiological estimates obtained in the accompanying paper is consistent with the notion that reward-relevant MFB fibers arise in one or several rostral MFB nuclei.

Action Potentials↗
PubMedDate not supplied

Masseter and temporalis muscle EMG levels and bite force in migraineurs.

The purpose of this study was to compare absolute and proportional electromyography (EMG) levels in the masseter and temporalis muscles during performance of a variety of oral functions for migraineurs and age- and sex-matched controls. Both groups consisted of nine women and one man, with a mean age of 43 years (range, 29 to 51 years). Absolute resting EMG levels and those levels during swallowing and speech were not significantly different between the groups, but the levels of the group with migraine were significantly higher during maximum voluntary effort contractions on the anterior teeth and on the posterior teeth for both muscles. When expressed as a percentage of those levels obtained at maximal posterior contraction (ie, proportional levels), no difference in functional activity was demonstrated between groups. It was concluded that the two groups studied had similar levels of EMG activity in the masseter and temporalis muscles during the normal oral functions investigated, but that the group with migraine had higher levels of absolute EMG activity during anterior and posterior maximum voluntary contractions. Furthermore, the group with migraine demonstrated higher levels of anterior and posterior bite force, although not correlated with EMG levels.

Adult↗
PubMedDate not supplied

Application of genetically-engineered anti-CEA antibodies for potential immunotherapy of colorectal cancer.

Hitherto anti-CEA monoclonal antibodies (MAbs), normally of mouse origin, have been used primarily for clinical diagnosis of colorectal cancer, either as a tumor marker in serum to monitor tumor recurrence, or latterly as a means to localize in vivo CEA-bearing tumors, and metastases in patients. In vivo diagnosis using mouse anti-CEA MAbs has so far had limited clinical utility because the antibodies elicit a strong anti-mouse immunoglobulin immune response on repeated administration in man. This problem has been addressed by the development of various strategies for "humanization" of mouse anti-CEA MAbs by genetic manipulation of immunoglobulin genes. Such humanized, engineered antibodies markedly attenuate the antigenic response directed against the MAb, such that safe, repeated administration to patients has become feasible. Such humanized anti-CEA antibodies can thus be radioactively-labelled and applied for in vivo monitoring and detection of recurrent malignant disease, or used for therapeutic strategies which similarly take advantage of the ability of the antibodies to target cytotoxic agents selectively to tumor cells. The application of these novel procedures for manipulating MAb structure presents entirely new opportunities for diagnosis and treatment of human colorectal cancer.

Antibodies, Monoclonal↗