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Biomedical subjects

C M Brooks

Publications and source records attributed to C M Brooks.

At least 19 recordsLinked to original sources

Organizational planning: a program evaluation survey of AACE members.

The Long Range Planning Committee of the American Association for Cancer Education (AACE) has completed a comprehensive survey of AACE members. The survey was distributed in July and August 1989 to 592 AACE members, and 360 (61%) returned completed forms. The respondents did not differ markedly from the membership as a whole on selected member characteristics. Survey questions addressed the following aspects of the AACE: Annual Meeting, Special Interest Sections, Liaison Relationships, Journal of Cancer Education (JCE), and Communications. Results showed that the AACE is healthy and responsive to the needs of its members. Several areas needing attention were indicated, but no significant concerns were noted.

Communication

Survey design and observations relating to cancer education funding. Cancer Education Survey II: cancer education in United States medical schools (conducted by The American Association for Cancer Education with the support of the American Cancer Society).

A survey has been conducted of cancer education programs for medical students in United States medical schools by the American Association for Cancer Education with grant support from the Department of Detection and Treatment of the American Cancer Society (formerly the Professional Education Department). Two questionnaires were used, an Educational Resources Questionnaire (ERQ), which 126 of the 128 medical schools completed and returned, and a Faculty and Curriculum Questionnaire (FCQ), which was completed and returned by 1,035 faculty members who had been named as active in undergraduate medical student cancer education by respondents in each school who had been designated by the Dean's Office to complete the ERQ. Overall conclusions included: (1) increased coordination of cancer education activities is a major need in many schools; (2) there is widespread interest in the further development of cancer education objectives; (3) development of a national cancer education curriculum is needed; (4) there is interest in the development of improved instructional materials and methods; (5) development of evaluation methods is needed for cancer education programs; and (6) an ongoing funding process is needed to provide support for interdepartmental coordination of cancer education activities. Cancer prevention and detection topics were ranked above cancer treatment in plans for future curriculum emphasis. More detailed conclusions and recommendations are provided in this publication and three subsequent articles in this issue of the Journal of Cancer Education.

American Cancer Society

Instructional methods and the use of teaching resources in cancer education curricula. Cancer Education Survey II: cancer education in United States medical schools.

The findings on cancer teaching methodology presented in this abstract come from an American Association for Cancer Education (AACE)/American Cancer Society-sponsored survey of American allopathic medical schools in 1989 and 1990 to determine how and how well cancer is presented in the medical school curriculum. Responses were received from 126 institutional and approximately 1,000 faculty respondents. Approximately one-third (368) of faculty respondents indicated the use of specific learning objectives; utilization does vary across disciplines. The lecture remains the dominant form of instructional method. Computers were reported as an instructional modality by only 16% of the faculty respondents. Prepared audiovisual instructional materials appeared to be widely utilized. Use varied from 86% for 35mm slides to 11% for video discs. Faculty favored the development of new teaching materials for ten topic areas ranging from approximately 40% for early detection and prevention to a low of approximately 25% for rehabilitation and continuing care. The survey identified an underutilization of existing outpatient facilities and tumor registries for cancer teaching purposes. The findings give rise to questions concerning the appropriateness of the match between specific instructional goals and the teaching methods employed. Eight recommendations designed to strengthen cancer training are made.

Computer-Assisted Instruction

Cancer prevention education in United States medical schools. Cancer Education Survey II: cancer education in United States medical schools.

The Cancer Education Survey collected data from 126 of 128 US Medical Schools on the current status of cancer-related educational activities for undergraduate medical students. The study was conducted by a Supervisory Committee of the American Association for Cancer Education, with funding from the American Cancer Society. The survey obtained data concerning institutional characteristics in support of undergraduate medical student cancer education, ie, administrative structures, current cancer-related curricula, sources of financial support, and anticipated changes in these characteristics. Institutions were also queried on specific topics of cancer prevention, detection, and diagnosis that might be taught as identifiable areas of instruction for medical students. Three-fourths of the institutions had a lecture on the principles of cancer screening, and, among those, nearly three-fourths classified it as a part of a required course or rotation. Detection of common cancers is taught in virtually all institutions. The least likely cancer prevention lecture topics are related to prevention and cessation of smoking, a well-verified cancer risk. Also, no consistent pattern emerges that might indicate that association with a cancer center imparts to a medical school a greater emphasis on delivery of cancer prevention topics.

American Cancer Society

Changing the cancer curriculum: a curriculum committee's response to the results of the AACE Cancer Education Survey II. Cancer Education Survey II: cancer education in United States medical schools.

The AACE Cancer Education Survey-II offers an unusual opportunity based on data from 125 medical schools and 1,035 experienced cancer educators to effect constructive change with regard to cancer education. The changes suggested include more coordination; integration; and a shift of emphasis to include more on topics of prevention, early diagnosis, tumor biology, rehabilitation, palliative care, and psychosocial issues. Ample opportunities, especially in the ambulatory care arena, exist at most medical schools, and there is a great deal of interest in improving the situation. This article reviews the factors contributing to resistance to change, the data on adult learning, and the major movements and dilemmas facing medical education today. It also discusses some of the external forces like the Liaison Committee on Medical Education (LCME) and foundation support, which are being harnessed to effect change. Given these barriers, forces, and opportunities, the article ends with a possible action plan for an individual, an institution, and national bodies interested in cancer education. The knowledge, skills, values, and attitudes must be defined, taught effectively, and evaluated. It is an opportune time, armed with this useful data, to bring about change in how cancer subjects are taught. The ultimate goal is more knowledgeable and effective practitioners and scientists who can decrease the morbidity and mortality from cancer.

Curriculum

A meal conference format to teach ambulatory nutrition concepts.

Third-year medical students participated in a program using a meal conference approach to teach ambulatory nutrition concepts called "Building Better Health Through Nutrition." The series of three interactive presentations was given during the required family medicine clerkship. A pretest and posttest were used to measure acquisition of nutrition knowledge. There was a statistically significant (P less than 0.05) average increase in posttest compared to pretest scores. Seventy percent of students rated the meal conference approach as "effective" or "very effective" and 76% stated that the series expanded their knowledge of nutrition's role in clinical medicine. We conclude that the meal conference format is an effective way to teach nutrition during the clinical years in medical school.

Ambulatory Care

Features of asthma in older adults.

A study compared clinical and functional features of elderly patients with asthma to younger patients at a university medical center. Older patients had a larger than predicted reduction in pulmonary function parameters even though physician-assessed severity, duration of diagnosed asthma, and smoking status were no different between groups. A significant increase in the comorbid diagnosis of chronic obstructive pulmonary disease was noted in older patients with asthma. These two points support the hypothesis that long-standing asthma may lead to irreversible airflow obstruction. Older patients reported better medication compliance and decreases in some respiratory symptoms and demonstrated lower health care utilization.

Adolescent

Rhythmic patterns of discharge in hypothalamic neurosecretory neurons of cats and dogs.

Recent studies in rats suggest that vasopressin- and oxytocin-secreting neurons in supraoptic nuclei and paraventricular nuclei of the hypothalamus show two different patterns of activity: one a "bursting" or rhythmic pattern and the other, irregular continuous discharges. This possibility was investigated in cats and dogs anesthetized with chloralose or Nembutal by recording electrical activity of single supraoptic and paraventricular neurons. Only some of the "identified" neurosecretory cells showed rhythmic, intermittent discharges ("bursting" cells in rats); the majority showed an irregular continuous firing pattern. Furthermore, the pattern of discharge sometimes changed from one ot the other during long periods of observation. This occurred without apparent stimulus in certain instances; in others, the rhythmic firing was associated with fluctuation in blood pressure and heart rate and was likely to be caused by changes in baroreceptor activity. Possible origins of rhythmic discharges and the physiological importance of such patterns in terms of hormone secretion are discussed.

Action Potentials

Study of cardiac sympathetic and vagal efferent activity during reflex responses produced by stretch of the atria.

(1) In chloralose anesthetized dogs, effects of the left and the right atrial stretch were studied in the same animal. Stretch of the sino-atrial region of the right atrium produced acceleration of the heart rate during, and reversal of response at the termination of, the stretch. Stretch of the left pulmonary vein-atrial junctional region evoked an initial decrease followed by an increase in heart rate. The responses were similar in all animals, despite initial heart rates ranging from 120 to 200 beats per minute. (2) Activity in vagal and sympathetic nerve branches innervating the heart was recorded simultaneously. Care was taken to identify the vagal fibers innervating the heart, and record their activity without contamination of sympathetic impulses. The right atrial stretch evoked an augmentation of sympathetic activity which reached its peak at 20 sec after the beginning of stimulus. The stimulus slightly increased the vagal activity; this change occurred slowly and reached its peak in about 40-60 sec after stretch. At the release of stretch, sympathetic activity generally showed a reversal of response, i.e. activity was inhibited for 30 sec. (3) Stretch of the left atrium produced biphasic changes in cardiac sympathetic nerves; their activity was strongly inhibited for the first 15 sec, then augmented throughout the remainder of the stretch. This effect lasted 30 sec after the cessation of stimulus. Effects on vagal cardiac nerve fibers were smaller; mild augmentation in activity was produced. The onset of this effect was faster than that seen in case of the right atrium stretch. (4) Reciprocal action between vagal and sympathetic cardiac nerves was obvious only in the early phase of left atrium stretch. Effects on the heart were determined by balances in activity of these antagonistic nerves. In contrast with what occurred in cardiac reflexes, carotid sinus distension even in the same animal produced a large increase in vagal activity, and near complete inhibition of sympathetic nerve activity. Thus, good reciprocal action between the two sets of nerves was demonstrated. A difference in the two types of reflexes was thus revealed. (5) Stretch of the right atrium evoked during carotid sinus distension caused an increase in heart rate from the new low level which was produced by baroreceptor activation. Vagal activity which was greatly augmented by sinus distension was decreased by atrial stretch, while previously inhibited sympathetic activity due to sinus distension was augmented by stretch of the atrium. The effect of stretch on vagal activity seems to depend to a degree on the prestimulus level. It is of interest that the powerful baroreceptor reflexes do not mask the cardiac reflexes studied. (6) The relative importance of sympathetic and vagal efferents to atrial stretch reflexes was discussed.

Animals

Factors affecting overdrive suppression of idioventricular pacemakers and associated potassium shifts.

A characterization of the factors controlling overdrive suppression of idioventricular pacemakers was investigated in canine hearts with complete atrioventricular block perfused in vitro. The following results were obtained: 1) overdrive suppression increases as a function of driving rate in a sigmoidal fashion; 2) overdrive suppression is maximal after 3 min; 3) the pause is a function of spontaneous rate prior to overdrive; 4) overdrive causes an initial net K loss; 5) overdrive is followed by a transient net K grain; 6) increasing [K]o does not affect K loss; 7) net K loss with drive is less in pre-driven hearts; 8) net K uptake after overdrive is little affected by ventricular activity; 9) acetylcholine does not alter ventricular K balance; and 10) paired stimulation increases overdrive suppression and K loss whether or not each stimulus is followed by a contraction. The following conclusions are drawn. The factors controlling overdrive suppression include the spontaneous rate prior to drive, the rate, duration and pattern of drive, an increase in [K]o during the drive and a decrease in [K]o after drive, but not on acetylcholine-mediated inhibition.

Acetylcholine

Nature of differential sympathetic discharges in chemoreceptor reflexes.

In a study of autonomic reflexes it was found that some produce a generalized, bilaterally uniform response whereas others have an asymmetric or laterality of action. Recordings from vertebral nerve fibers (mainly vasoconstrictors to forelimb muscles), right and left cardiac sympathetics, and renal nerves show that baroreceptors evoke a bilaterally uniform inhibition but chemoreceptors of the carotid sinus and aortic arch initiate a differential discharge. In the chemoreceptor reflex the vagi are activated and bradycardia generally occurs. Vertebral and renal sympathetic fibers increase their activity bilaterally commensurate with the increase in arterial pressure. Sympathetic discharges to the heart, however, are not uniform; they show ipsilateral inhibition and a strong contralateral increase in activity. Stabilization of blood pressure or inactivation of baroreceptors abolishes the ipsilateral inhibition. In isolation, therefore, the chemoreceptor-induced cardiac sympathetic discharge is just quantitatively stronger contralaterally. In the absence of vagi, heart rate changes differ depending on which chemoreceptors are stimulated, because the pacemaker is on the right. Asymmetrical discharges do occur and, in the eventual response to stimulation of chemoreceptors, reflex interactions actually augment the laterality of effects. Peripheral interactions, in the sense that changes effected by one may induce another reflex, are responsible in part for the balances of autonomic activity ultimately seen as the body reacts to stimuli.

Animals

Interaction of oscillators: effect of sinusoidal stretching of the sinoatrial node on nodal rhythm.

In this study of factors affecting and integrating activity of cardiac tissues, isolated strips of rabbit atria containing the sinoatrial node were subject to sinusoidal stretch. Effects on electrical discharge rates and rhythm of this pacemaker were observed. Repetitive stretch of a few millimeters (20-40% increase in length) caused acceleration and produced oscillations in rate which were roughly proportional to frequency of stretching. At fast frequencies of stretching, the sinus rates oscillated faster but not synchronously. When rate of stretching approached the "resting" rate of the sinus, a "lock'in" occurred, in that sinus rate accelerated but oscillations disappeared. During stretching rates approximately twice resting rate, the oscillations again disappeared. At rates of stretching during which oscillations were synchronous, the time of pacemaker firing changed to coincide with the peak phase of the applied sinusoidal stretch, although several seconds were required for this adjustment. Interval histograms also showed that application of sinusoidal stretch imposed a greater regularity on pacemaker action. It was thus demonstrated that oscillatory processes of the cardiac pacemaker and an interaction of oscillators conceivably can occur in the heart. (Preliminary Publication, The Physiologist, 16 "3, 1973.)

Animals

Interaction of oscillatory processes: the effects of subthreshold A.C. current on sinoatrial nodal rhythm.

In this study of interactions occurring within the heart, isolated superfused strips of rabbit atria, containing the sinoatrial (s.a.) node, were subjected to sinusoidal subthreshold current pulses of varied frequencies and intensities. A.C. current from an R.C. oscillator was applied through a Grass stimulation isolation unit, push-pull connection, and non-polarizing (Ag-AgCl-KCl-Tyrode Agar-Agar) electrodes. A Grass polygraph and tachometer were used to record the applied pulses and nodal firing rates; simultaneous magnetic tape recordings were obtained and used for data analysis. Suction electrode recordings and oscilloscope displays were used to determine how the cyclic impulses affected cellular activity. The s.a. nodal rhythm was modified by subthreshold A.C. current applications; when frequencies were low, firing rates of the node were modulated by the A.C. and mean rates were reduced. As frequencies were progressively increased, slow waxings and wanings in heart rate were produced. These periodic fluctuations were not readily correlated with either the A.C. frequency nor the intrinsic nodal rate, but were representative of the difference between the two. As applied current frequency neared the pacemaker's intrinsic rate, a synchronization occurred and the discharges locked in at a specific phase of the applied current alternation. This synchronization maintained during slight further increases in A.C. frequency but above a critical rate this relationship broke down and the waxing and wanings in frequency of pacemaker rate again developed. It was concluded that pacemaker action of the s.a. node is effected by integration of cellular activity through electron coupling.

Action Potentials

Interaction of myogenic and neurogenic mechanisms that control heart rate.

Interaction of neurogenic and myogenic factors that control heart rate was studied. Sympathetic nerve actions and stretch of the sinoatrial node both have an accelerator effect which appears to be competitive, and additive rather than facilitatory. In contrast with this, the accelerator effects of sinoatrial node stretch were proportionately greater when stretch was applied during a slowing produced by vagus nerve stimulation. The hyperpolarizing effect of vagus nerve stimulation or acetylcholine apparently potentiates the accelerator effects consquent to the depolarizing actions of stretch. The myogenic reaction can be considered as playing a role in maintaining cardiac output and preventing excessive slowing or diastolic distension and a deficient circulation.

Acetylcholine

Centers involved in the autonomic reflex reactions originating from stretching of the atria.

Stretching the atria in anesthetized dogs produces reflex changes in heart rate, and in cardiac and renal sympathetic nerve activity. Anemic decerebration, cord transection at C4-C5, and severance of vagal or sympathetic cardiac nerves was done to identify the pathways and centers essential for these reflexes. Stretching the right atrium produced an aceleration of the heart and a definite increase in sympathetic nerve activity. Left atrial-stretch caused biphasic responses: an initial sympathetic nerve inhibition and slower heartbeat folowed by sympathetic excitation and heart acceleration. The afferents responsible were carried mainly by the vagi; efferent neural control of the heart was mostly sympathetic. The reflex inhibition observed was integrated chiefly at the medullary level, but supramedullary structures contributed to the augmentation in sympathetic activity and heart rate. When central connections between vagal afferent and sympathetic efferent pathways were separated by cord transection, atrial stretch caused a decrease in heart rate due to reflex action through the vagal loop. After the cord was sectioned, we found that some afferent impulses from the atria traveling in sympathetic nerves produced a slight reflex augmentation of sympathetic efferent activity, though insufficient to affect the heart rate. Somatosympathetic reflexes evoked in cardiac and renal sympathetic nerves by stimulation of various somatic afferent pathways were also affected by atrial stretch indicating central nervous system interactions. Reflex responses to right atrial stretch were superimposed on accelerations of myogenic origin.

Action Potentials

Continuous low dose peripheral vein pitressin infusion in the control of variceal bleeding.

Continuous low dose peripheral vein pitressin has been shown to be effective in controlling variceal bleeding in seven episodes of bleeding in six patients. No significant side-effects were seen. The expense, delay and hazard associated with superior mesenteric artery catheterization for selective arterial pitressin infusion were avoided. If these results can be reproduced, low dose peripheral vein pitressin infusion may prove to be a valuable addition to the treatment of bleeding esophageal varices.

Adult