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Biomedical subjects

W E Walker

Publications and source records attributed to W E Walker.

At least 19 recordsLinked to original sources
PubMed1990

Surgical treatment of cardiac tumors: a 25-year experience.

From 1964 to 1989, we performed operations on 133 patients with cardiac tumors. There were 58 male and 75 female patients ranging in age from three days to 81 years; 101 were adults, and 32 were children (less than 12 years of age). Primary tumors (102 benign and 12 malignant) were found in 114 patients and metastatic tumors in 19. Symptoms included congestive heart failure, arrhythmias, emboli, and chest pain. Diagnosis was accomplished through angiography, echocardiography, computed tomography, and magnetic resonance imaging. Operative treatment encompassed techniques ranging from biopsy to complete excision (including hypothermic circulatory arrest and cardiac autotransplantation) depending on the site of disease and the extent of involvement. Overall operative survival was 91%. Twelve patients died early (within 30 days of operation), and follow-up was obtained for 110 (90.9%) of the remaining 121 survivors (total patient-years of follow-up, 572.8; mean follow-up, 5.2 years). Of the 20 patients who died late, 15 had malignant disease. Operative survival for patients with primary cardiac malignancies and for those with metastatic disease was 83% and 68.4%, respectively, with 3 and 5 patients, respectively, still living. We advocate an aggressive surgical approach, especially in patients with benign tumors, who can expect an excellent outcome. For patients with malignant or metastatic disease, palliation and cure are also possible if aggressive surgical actions are taken.

Adenocarcinoma↗
PubMed1979

Cholangitis with a silver lining.

Acute obstructive cholangitis developed secondary to a common duct stone formed around a silver hemostatic clip, introduced at cholecystectomy two years previously, that had migrated from a long cystic duct remnant. Stone formation around a silk suture is well known, and silver clips in the area of the porta hepatis may constitute a similar hazard.

Cholangiography↗
PubMed1979

Reparative cardiac surgery in infants and small children: Five years experience with profound hypothermia and circulatory arrest.

A five year experience of profound hypothermia and circulatory arrest in the operative management of severe congenital heart disease in 128 infants and children weighing 10 kg or less is reviewed. Hospital mortality was 13% for the entire series--8% in the last two years. Mortality varied with the defect present rather than with the age at operation, and appeared to decline over the five years. There was no morbidity associated particularly with this technique, and no evidence of permanent neurologic nor intellectual impairment. Total arrest time averaged 55 minutes, was related significantly to the defect being repaired, but was not related to hospital mortality. The results support the idea of definitive early cardiac repair for severely symptomatic infants and young children, rather than surgical palliation. The hypothermic arrest technique is attractive since it allows optimal operating conditions, thus permitting an accurate repair and the consequent improvement in surgical results.

Child, Preschool↗
PubMed1978

Clinical application of a single compartment model to urea and creatinine kinetics in dialysis therapy.

A single compartment mathematical model has been shown to accurately described changing serum concentrations of low molecular weight solutes (urea and creatinine) during dialysis. Clinical application of the model permits prediction of serum concentrations in response to changes in prescription of dialysis therapy. The programs presented here can be used to predict the effect of changes in treatment time and dialyzer clearance on serum concentrations. Sequential pre- and end-dialysis solute concentrations are displayed on a programmable pocket calculator. Dialyzer clearance during any individual dialysis can be calculated. These programs permit an evaluation of the efficacy of prescribed dialysis treatment schedules in advance of therapeutic trials.

Computers↗
PubMed1978

Relationship of state-trait anxiety and type of practice to reading comprehension.

The effects of state-trait anxiety and distribution of practice on reading comprehension were studied in male and female undergraduates of average aptitude. In Experiment 1 no significant differences were found on an 8-item test between 18 high and 18 low A-trait students who studied a reading passage with a 5-sec or 2-min intertrial interval. Experiment 2 employed a total of 60 students, a state-trait measure of anxiety, a 36-item test, ego-involving instructions, and 5-sec or 2-min intertrial intervals. The following significant (p less than .05) results were found: (a) high A-trait students responded to the ego-involving instructions with greater elevations in A-state; (b) low A-trait students demonstrated superior reading comprehension; (c) a low level of A-state immediately prior to the comprehension test produced a higher test score; (d) the A-state level of high A-trait students was reduced with the 2-min intertrial interval. Collectively, the results supported a trait-state conceptualization of anxiety.

Achievement↗
PubMed1978

Vascular reconstructive surgery following myocardial revascularization.

Survivors of successful coronary bypass have a life expectancy close to normal. Myocardial infarction has been the major cause for morbidity and mortality in patients requiring surgery. Current data suggests that patients who have undergone CAB are not only acceptable risks for subsequent surgery, but may in fact have a lesser cardiac risk than the routine patient. The selection of the proper sequential surgical procedures is critical for patient survival. We reviewed 74 major vascular reconstructive procedures in 53 patients. Twenty-nine cerebrovascular procedures, 20 femoro-popliteal bypasses, aneurysmectomy nine times, and aortic bypass in 16 patients were the procedures performed. Twenty-two abdominal operations were performed with no significant morbidity or mortality. Two patients died during the postoperative period and three have subsequently died. The 48 survivors continue to do well.

Adult↗
PubMed1978

Further evaluation of the surgical treatment of obstructive disease of the left main coronary artery.

A protocol for the operative management of two patient groups with left main coronary artery disease has been evaluated. The period prior to and during induction of anesthesia is managed without using aortic balloon counterpulsation. Of the 86 patients undergoing coronary artery bypass for left main coronary artery disease from 1970 to 1973, there was a surgical mortality of 8.1%. Follow-up of the survivors from 48 to 87 months revealed three coronary and five non-coronary related deaths with survival to seven years of 75.6 +/- 5%. If the operative mortality is excluded, there is an observed survival to seven years of 82.4 +/- 4.8%, almost the same as a "normal" population of similar age and sex. Utilizing the same protocol, 90 similar patients undergoing coronary artery bypass in 1976 had an operative mortality of 4.4%. The deaths were not related to induction of anesthesia. The perioperative infarction rate (2%) and postoperative cardiac enzyme determinations were no greater in a random group having the same operation for less severe forms of coronary artery disease during the same time period. This method of management for patients with significant left main coronary artery disease is judged superior to other more complex techniques.

Coronary Artery Bypass↗
PubMed1978

Relation between component parts of fibrocystic disease complex and breast cancer.

Specimens of benign breast disease obtained from biopsies performed at Vanderbilt Hospital (Nashville, Tenn.) between 1952 and 1959 were histologically reviewed and characterized as to individual component types of fibrocystic disease. Follow-up for information regarding breast cancer development was 94% successful. Carcinoma developed more often when epithelial proliferative lesions were present. Atypical lobular hyperplasia had a greater predictive value than other epithelial lesions and was associated with an elevated risk six times that expected prior to the age of 45 years and a tripling of risk after the age of 45 years. Various ductal hyperplastic lesions are associated with approximately a doubly increased risk that is present only if the lesions are identified at biopsy after the age of 45 years. Women with cysts, sclerosing adenosis, fibrosis, and other nonhyperplastic changes were at no greater risk for subsequent carcinoma than women in the general population.

Adenofibroma↗
PubMed1978

Techniques and results of ventricular aneurysmectomy with emphasis on anteroseptal repair.

We have reviewed an 8 year experience with ventricular aneurysmectomy in 170 patients. Ninety percent had anterior aneurysms and underwent "anteroseptal repair" with exclusion of nonfunctioning septal myocardium. Preoperative left ventriculograms and coronary arteriograms were studied and "scored," and the hospital mortality and long-term survival rates for various subsets of the group were correlated with their radiographic data. A postoperative score for the coronary arteries was developed according to the preoperative anatomy and the vessels bypassed. Both the ventriculogram score and the postoperative coronary score had significant effects on both hospital mortality and long-term survival rates. The severity of preoperative coronary disease had minimal predictive value. Recent myocardial infarction did not preclude a good result. The value of an aggressive surgical approach to patients with ventricular aneurysm was confirmed even for certain subsets with indicators suggestive of poor prognosis. Anteroseptal repair appears to give optimal results for the typical "anterior" aneurysm. All suitable coronary arteries should be bypassed. Attention to the details of preoperative anatomy and function allows the most accurate prediction of prognosis and dictates the optimal therapeutic approach.

Adult↗
PubMed1977

Input impedance of the systemic circulation in man.

To determine the systemic input impedance, pulsatile pressure and flow were measured in the ascending aorta in 16 human subjects who were undergoing diagnostic cardiac catheterization. Blood flow was measured with a catheter-tip electromagnetic velocity meter, and pressure with an external transducer connected with the fluid-filled lumen of the catheter. Five subjects were found to have no evidence of cardiovascular disease (group A, mean age 32 +/- 2 years, mean aortic pressure 97 +/- 4 mm Hg). Seven had clinical and angiographic signs of coronary arterial disease, and mean pressures less than 100 mm Hg (group B, mean age 48 +/- 2 years). Four subjects had signs of coronary disease and mean pressures greater than 100 mm Hg (group C, mean age 48 +/- 3 years). The frequency spectra of impedance were qualitatively similar in all three groups and resembled those previously observed in the canine aorta. Characteristic impedance was lower in the normal subjects (group A, average 53 dyn sec cm-5) than in the subjects with coronary artery disease (groups B and C, average 129 dyn sec cm-5). Among the subjects with coronary disease, characteristic impedance was higher in the hypertensive subjects (group C, average 202 dyn sec cm-5) than in those with lower mean pressures (group B, average 95 dyn sec cm-5). External left ventricular work per unit time (hydraulic power) averaged 1715 milliwatts (mW) in group A, 1120 mW in group B, and 2372 mW in group C. Cardiac outputs were within normal limits in all subjects, but tended to be lower in group B than in group C. These results suggest that the subjects of group C were better able to meet the increased energy demands imposed by an abnormally high aortic input impedance. Further investigation is needed to learn whether the high impedances in subjects with coronary disease represent an increase with age and transmural pressure alone, or whether some additional factor is involved. The data on relatively normal subjects permit a tentative definition of the normal limits for aortic input impedance in man: 26-80 dyn sec cm-5.

Adult↗
PubMed1976

Physostigmine--its use and abuse.

Physostigmine salicylate, a cholinesterase inhibitor, has been shown to reverse the effects of certain drugs with anticholinergic properties. The paper provides a brief historical account of physostigmine, reviews the cholinergic drugs and their effects and suggests a management protocol based on physiologic criteria. Twenty-six overdose cases, recently treated with physostigmine, are summarized. The controversy regarding the etiology of seizures following physostigmine administration is discussed.

Cholinesterase Inhibitors↗
PubMed1975

Application of a programmable pocket calculator to a single compartment mathematical model of solute kinetics.

A single compartment mathematical model has been applied to kinetics of small solutes (urea and creatinine) in dialysis therapy. The model can be described by two equations requiring iterative solution of calculated values, given several measurable variables. The equations have been programmed onto a Hewlett-Packard 65 pocket calculator and recorded on 3 X 1/2" magnetic strips, facilitating clinical application to dialysis therapy.

Computers↗
PubMed1975

Salivary gland carcinoma of the palate.

Results of a detailed study of the clinical features, histology, management, and prognosis of palatal carcinoma of salivary origin in 30 patients are presented. These were compared to a larger series of salivary carcinoma at other sites, and to the known behavior of epidermoid carcinoma of the palate. The prognosis was significantly better for lesions of the palate. Results of treatment were also much better for these salivary gland lesions than for epidermoid carcinoma of the palate. The frequent occurrence and seemingly greater malignancy of adenoid cystic carcinoma at this anatomic site are stressed. Several patients with primary bone involvement survived, but local recurrence in the maxilla carried a graver prognosis. There was no definite indication that radiotherapy altered the course of the disease, and nothing to suggest that prophylactic neck dissection is of value. On the basis of the evidence presented, there is little to justify more radical excision than the clinical extent of the lesion would indicate, with the probable exception of adenoid cystic carcinoma, where a more aggressive approach may well prevent death from cancer.

Adult↗