Sharing food in the stomachs of seabirds between adults and chicks--a case for delayed gastric emptying

1. Retention times of food in stomachs of breeding and non-breeding African pengiuns (Spheniscus demersus) were examined. 2. Rates of gastric emptying in non-breeding birds were linearly related to the mass of food in the stomach. 3. Breeding birds returned to the nest with more food in their stomachs when chicks were larger. The rate of regurgitation of food was linearly related to chick mass. 4. Retention times of food in the stomachs of breeding penguins can only be explain by cognisance of observed regurgitation rates and by assuming that there is no gastric emptying through the pyloric sphincter.

Mechanism of calcium-dependent inactivation of a potassium current in Aplysia neuron R15: interaction between calcium and cyclic AMP

In the preceding paper (Kramer and Levitan, 1988), we presented evidence that an inwardly rectifying K+ current (IR) is inactivated by Ca2+ influx accompanying spontaneous bursting activity in the Aplysia neuron R15. In this paper we examine the mechanism that enables Ca2+ to inactivate IR. Since IR is enhanced by cyclic AMP in neuron R15 (Drummond et al., 1980; Benson and Levitan, 1983), we examined the Ca2+-dependent inactivation of IR after application of either serotonin (5-HT), the adenylate cyclase activator forskolin, or a membrane-permeable cAMP analog, all agents that increase cAMP and hence the magnitude of IR. Even though more active IR channels are available under these conditions, less Ca2+-dependent inactivation is observed. This is contrasted with the Ca2+-dependent inactivation of the voltage-gated Ca2+ current (ICa). Elevating cAMP enhances ICa in R15 and also increases its Ca2+-dependent inactivation. Hence the mechanisms whereby Ca2+ inactivates IR and ICa appear to differ from each other. Elevating internal Ca2+ by repeatedly depolarizing the neuron suppresses the response of IR to brief applications of 5-HT, and speeds the relaxation of the response, suggesting that Ca2+ can interfere with the cAMP-dependent activation of IR. One biochemical site where Ca2+ can reduce cellular cAMP is by activating the Ca2+/calmodulin-sensitive form of phosphodiesterase. We have detected such enzyme activity in homogenates of Aplysia abdominal ganglia and extracts of single R15 somata. Inhibitors of the phosphodiesterase activity suppress the Ca2+-dependent inactivation of IR. Finally, we have used a radioimmunoassay to measure cAMP in individual R15 somata, and have found that R15 neurons hyperpolarized for prolonged periods contain more cAMP than do R15 neurons allowed to burst, consistent with the hypothesis that Ca2+ influx reduces cAMP.(ABSTRACT TRUNCATED AT 250 WORDS)

Integrated Academic Information Management Systems (IAIMS). Part II. Planning and implementing integrated information services. The management of change: lessons learned from the IAIMS experience

The critical elements of the change process were designed into the strategic planning process and the pilot project for the Integrated Academic Information Management System (IAIMS) at the University of Maryland. These elements were: Support by the institutional leadership; a critical mass of interested participants from diverse groups across the organization, committed to the project and with ownership of the plan; a motivating level of dissatisfaction with the status quo; the construction of a scenario describing the desired future and an assessment of needs to achieve it; technical and consulting help; a pilot project with replicable features to demonstrate the concept and feasibility of the approach; and participation of opinion leaders initially with later identification of additional opinion leaders who would become part of the pattern of acceptance of the innovation and diffusion of the technology across the campus.

Making a difference--women, medicine, and the twenty-first century

Women can and should make a difference in how medical care is given in the future. The increased number of women physicians presents an opportunity to make a significant impact on the quality of medical care. Data is provided on the number of women applicants to medical school, matriculants and graduates, specialty choices, the status of women in academic medicine, and the income of women physicians. Four aspects of the environment that portend important changes for medicine in the future are identified: scientific developments, alternative delivery systems and the corporate practice of medicine, the aging population and other demographic changes, and the expanding number of physicians. Some of these changes suggest opportunities for making a difference in the traditional specialties of medicine, in providing care to underserved populations, in research careers, in the shortage areas of preventive medicine and public health, occupational medicine, child psychiatry, and physical medicine and rehabilitation, and in new areas such as community pediatrics, behavioral pediatrics, and adolescent medicine. There are many choices and many decisions to be made, and each individual can choose to make a difference.

The IAIMS initiative at the University of Maryland at Baltimore

With support from the National Library of Medicine, the University of Maryland at Baltimore is creating an Integrated Academic Information Management System (IAIMS) that will serve as a prototype for academic health centers. A campus-wide undertaking, the IAIMS initiative at Maryland is characterized by its functional comprehensiveness and its planning model. The resulting strategic plan is serving as a guide in the ongoing model development within an interdisciplinary Hypertension Center.

Brain enzyme and clinical alterations induced in rats and mice by nitroaliphatic toxicants

The effects of a single subcutaneous (s.c.) injection of the nitroaliphatic toxicants 3-nitropropanol (NPOH) and 3-nitropropionic acid (NPA) dissolved in physiological saline solution were studied in mice and rats, respectively. Clinical signs observed in both NPOH-treated mice and NPA-treated rats included depression, abnormal motor activity, and recumbency. Succinate dehydrogenase (SDH) activity, demonstrated histochemically in frozen brain sections, was markedly reduced in intoxicated mice and rats. The SDH activity of mitochondrial preparations from brains of intoxicated mice and rats was diminished to 18-24% of control values, although the activity of another mitochondrial flavoprotein enzyme, alpha-glycerophosphate dehydrogenase (alpha-GPDH), was not altered.

Tenure in medical schools in the 1980s

Tenure in American medical schools is a personnel policy which exists in relation to institutional policies and realities. It is related to the functions of academic institutions and their capacity for carrying out these functions, and it arises from the needs of an open society to sustain critical and innovative roles for its universities, the necessity for universities to support and protect their faculties, the optimization of their capability to react to new opportunities, and the demands of ever shifting social circumstances. The relation between society and its universities and the balance among the various roles of the universities have not been stable in the past and will not be so in the future. Tenure policies will continue to be modified. The leadership of institutions needs to be aware of the fact that the modifications will occur and of what might be termed the plasticity of tenure.

The four horsemen of the apocalypse. Study of academic medical center governance

Governance of academic medical centers is in a process of change. This essay reviews some of the historical factors that have affected the present status of academic medical center governance and describes the functions of the four individuals who are most involved in the operation of academic medical centers: vice-presidents for health affairs, deans of relationships between these four individuals are analyzed, and points of conflict are identified. Some suggestion about how these individuals can work together more effectively are made.

Masking of noise bursts by an adjacent vowel for hearing-impaired listeners

Some masking effects of synthetic vowels on adjacent noise bursts are reported for hearing-impaired listeners. The 200-ms vowels were similar to [a] and [i]; the 50-ms noise bursts were in one of three frequency bands: .5 to 1.5, 1.5 to 4, or 4 to 6 kHz. With voiceless-stop-like temporal intervals between the stimuli, there was little backward or forward masking of the noise bursts by either vowel. Some forward masking occurred under proximate conditions of vowel and burst in time and frequency.

Backward and forward masking in listeners with severe sensorineural hearing loss

Using synthetic stimuli, backward and forward masking by a first-formant stimulus were measured for two tasks: (1) discrimination of a second-formant transition and (2) pure-tone detection. 16 listeners with moderate to severe sensorineural hearing impairment were studied. Many of the listeners showed backward and forward discrimination masking, sometimes extending as far as 200 ms before or after the first-formant interval. There were large individual differences in degree and temporal extent of masking. The masking contribution of sensitivity shifts, as indicated by pure-tone detection levels, appeared to be limited to a range of only 50 ms before or after the first-formant masker.

Implications of planning for regional libraries: our underlying philosophy

The National Library of Medicine Extramural Program in administering the Medical Library Assistance Act of 1965 has developed the following specific program objectives: provide financial assistance for improving biomedical libraries; encourage and assist the establishment and functioning of a responsive national biomedical information network by strengthening present biomedical libraries and their interlibrary relationships; and assure that the biomedical library network is linked to related science information systems. The ultimate goal is to develop the role of the library as a full learning resource center for education, research, and service. The regional library program aims to augment present capability of existing medical libraries so that information can be made available more extensively and more rapidly. Comprehensive and thorough advanced planning is a basic element in the development of regional medical libraries.

Extramural programs of theNational Library of Medicine: program objectives and present status

The National Library of Medicine Extramural Program, utilizing the authorities of the Medical Library Assistance Act of 1965 and the Public Health Service Act, includes support for library construction, improving and expanding basic library resources, research and development, man-power development, publications, and support for the operation of regional health sciences libraries. The program objectives relating to these various activities have been outlined. A $4,000,000 supplement has been appropriated by the Congress for fiscal year 1966 to implement the authorities of the Act. With the construction provision available in fiscal year 1967, over $13,000,000 has been requested for the second year of the program. The Medical Library Assistance Act is intended to catalyze and stimulate expanded support of medical libraries by their host institutions. Bold and imaginative plans by the medical library community are essential to the full success of the endeavor.