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PubMed1981

Is the doubly deleted alpha-thalassemia gene a "fugitive" allele?

The alpha-thalassemias (particularly in Asia) can be considered as a three-allele system, with one "normal" allele (N) consisting of a pair of closely linked alpha-chain loci, a second "single" allele (S) in which one of the loci has been lost by deletion, and a third "double" allele (D) in which both have been lost. Representatives of all the sets of fitnesses leading to the maintenance of this condition by selection for malaria resistance have been explored, and after the discarding of unlikely sets of fitnesses, it is found that there will be three outcomes: (1) the S chromosome is fixed, (2) the S and N chromosomes form a stable polymorphism, and (3) the N and D chromosomes form a stable polymorphism, but this can be lost and the population forced to fixation by the introduction of sufficiently large number of S chromosomes. Some Melanesian populations appear to have reached outcome (1), while frequencies in African, Mediterranean, and Middle Eastern populations are not incompatible with outcome (2). Southeast Asian populations, however, which carry S and D chromosomes in high frequency, may be in a state of flux. The D chromosome may form a polymorphism with N locally, but it can be driven from the local population by the introduction of large numbers of S chromosomes. The D chromosome would thus be somewhat analogous to a fugitive species, which can only exist in certain transient environments and is displaced as the environment changes. The possibility that N, S, and D are coexisting as a stable polymorphism can almost certainly be ruled out by a consideration of fitness sets required.

Alleles↗

PubMedDate not supplied

Iron, intracellular calcium ion, lipid peroxidation and carcino-genesis.

The evaluation of the accumulated experimental results on the action of complexed iron on cells indicates that the provoked cell injury is rather the consequence of an inhibition of the cytosolic Ca2+ concentration regulatory system than an effect of iron-induced lipid peroxidation. The role of the consequent intracellular ionic environment change in the preneoplastic and neoplastic transformation of the cell is discussed.

Animals↗

PubMedDate not supplied

Moving from the operating room to home care.

Although a change in career can be frightening, a nurse can reap many benefits in a change to home care nursing. With the health care environment changing, home care is increasing and offers a nurse a chance to refresh her enthusiasm for individual patient care and put to use her collective skills learned along the way.

Career Mobility↗

PubMed1976

Lac Repressor. Fluorescence of the two tryptophans.

By comparing the fluorescence emission properties of the wild type lac repressor with two lac repressors altered at tryptophan 190 and 209, respectively, we show that tryptophan residue 209 has its environment changed, either by its own motion, or that of the surrounding amino acids when an inducer molecule is bound. Substitution of this tryptophan with other amino acids results in lac respressor molecules with reduced affinity for inducer molecules, indicating that the geometry at residue 209 affects the geometry of the inducer-binding site. From the results of potassium iodide quenching of fluorescence from the tryptophans, and from attempts to react the native lac repressor with dimethyl(2-hydroxy-5-nitrobenzyl) sulfonium bromide and 2-hydroxy-5-nitrobenzyl bromide, we propose that tryptophan residue 209 is involved in a conformational change of the protein upon binding of inducer, but does not come in direct contact with inducer.

Amino Acids↗

PubMed1994

Reorganization: premises, processes, and pitfalls.

As the technological environment changes and libraries assume new and more active roles in their institutions, the traditional library hierarchy ceases to be an effective organizational structure. Guided by theories that emphasize teamwork, quality, and employee empowerment and participation, libraries are developing flatter, more networked organizations. The Health Sciences Library at Columbia University in New York, New York, recently underwent a reorganization in an effort to become a more resilient, more flexible organization. The process was beneficial overall. While some errors and confusion occurred, these are seen as opportunities for learning and evidence of the library's new atmosphere of creativity and experimentation.

Hospital Restructuring↗

PubMedDate not supplied

[Common memory aids of younger and older people].

This study investigates the use of internal and external mnemonics in everyday life. External mnemonics were assumed to be less capacity demanding than internal ones. Additionally, we expected the use of internal techniques to be reduced in western societies because of an environment changing towards a "world of external storing devices". Thirty students and 20 institutionalized old people were interviewed about their everyday use of mnemonics. The interviews were based on Harris' mnemonics questionnaire (1980). Our results indicate students using internal as well as external mnemonics, although for more external ones. In general, the same is true for the institutionalized elderly. However, 1) they mainly use external aids, and 2) in total, they use fewer mnemonics than students. These results contradict the general assumption of old people compensating for memory problems by increasingly relying on mnemonics. Instead, the dominance of external aids indicates a tendency to process information more economically. Overall, the results suggest the necessity of further investigating the conditions for a successful use of external aids in everyday life.

Adult↗

PubMedDate not supplied

How a better understanding of transformational leadership can help improve your practice as a nurse administrator.

Nursing administrators of today find themselves practising in an environment of permanent whitewater--an environment of chaotic change. Not only is the environment changing, so too are our employees: their needs, motives and priorities are vastly different than those we knew 20 years ago. The challenges of permanent whitewater cannot be overcome without effective leadership. Theorists agree that most North American organizations are currently overmanaged and underled. Certainly the leadership record of Canadian health care institutions has not been impressive. This paper will examine a selected set of concepts which the author believes are essential for nursing administrators who wish to provide real leadership to their departments and organizations: transformational (as compared to transactional) leadership; feminine (as compared to masculine) leadership; and empowerment. The literature review draws out both theory and practical applications.

Female↗

PubMed1995

From a regulatory lens: a perspective on the delegation of nursing activities to unlicensed assistive personnel.

Along with the reforming of health care, nursing services and related regulatory approaches are concurrently adapting. As the health care environment changes, the number and preparation of individuals who perform health-related activities has increased dramatically. Heightened interest is expressed at both ends of the nursing care delivery spectrum, unlicensed and advanced nursing practice. Boards of nursing, the States' regulatory arm over the profession, pay particular attention to public health and safety issues attached to the delegation of nursing tasks to unlicensed assistive personnel (UAPs). Equally important to the appropriate use of delegation is the provision of adequate supervision of those who are serving in the role of "delegatee." Mechanisms exist in a number of states whereby professional nurses can ascertain the level of competence of a UAP and feel assured that safe and appropriate care can be delegated. It is the role of the professional nurse to provide the required supervision, once a nursing activity is delegated. Nurse practice acts should not be used as barriers to escape required and prudent alterations to the traditional delivery of nursing care. Conversely, these same acts should not be manipulatively circumvented solely in the name of cost containment and as a needed response to "health care reform." As health care reforms, humanity would be best served with public or patient safety and protection as a guiding principle.

Facility Regulation and Control↗

PubMed1997

Prenatal stress induces high anxiety and postnatal handling induces low anxiety in adult offspring: correlation with stress-induced corticosterone secretion.

It is well known that the hypothalamo-pituitary-adrenal (HPA) axis is altered by early environmental experiences, particularly in the perinatal period. This may be one mechanism by which the environment changes the physiology of the animal such that individual differences in adult adaptative capabilities, such as behavioral reactivity and memory performance, are observable. To determine the origin of these behavioral individual differences, we have investigated whether the long-term influence of prenatal and postnatal experiences on emotional and cognitive behaviors in adult rats are correlated with changes in HPA activity. To this end, prenatal stress of rat dams during the last week of gestation and postnatal daily handling of rat pups during the first 3 weeks of life were used as two environmental manipulations. The behavioral reactivity of the adult offspring in response to novelty was evaluated using four different parameters: the number of visits to different arms in a Y-maze, the distance covered in an open field, the time spent in the corners of the open field, and the time spent in the open arms of an elevated plus-maze. Cognitive performance was assessed using a water maze and a two-trial memory test. Adult prenatally stressed rats showed high anxiety-like behavior, expressed as an escape behavior to novelty correlated with high secretion of corticosterone in response to stress, whereas adult handled rats exhibited low anxiety-like behavior, expressed as high exploratory behavior correlated with low secretion of corticosterone in response to stress. On the other hand, neither prenatal stress nor handling changed spatial learning or memory performance. Taken together, these results suggest that individual differences in adult emotional status may be governed by early environmental factors; however, perinatal experiences are not effective in influencing adult memory capacity.

Analysis of Variance↗

PubMedDate not supplied

IAIMS: planning for change.

The success of IAIMSs and other information technology plans depends to a great extent on the fit between the planning process and the nature of the organization. Planning processes differ as a function of both plurality of goals and the degree to which technology or the external environment changes. If all members of an organization share a common goal and the organization is in a relatively stable environment, the classic "plan, prototype, implement, evaluate" process may be appropriate. Most health care organizations are not consistent with this model. The components of the organization may have different goals, and both the health care environment and roles for technology are changing rapidly. In these circumstances, planning takes on a different light. This paper outlines approaches to IAIMS planning in various environments and provides a framework for IAIMS planning in rapidly changing environments.

Integrated Advanced Information Management Systems↗

PubMed1997

Expression of molecular biomarkers in primary breast tumors implanted into a surrogate host: increased levels of cyclins correlate with tumor progression.

BACKGROUND: The overexpression or amplification of tumor suppressor and proto-oncogenes are important factors in the progression of breast cancer. Recent attention has focused on the cyclin genes, whose involvement in signal transduction pathways regulate cell cycle progression. The amplification of the cyclins D1 and D3 genes usually leads to loss of normal growth control and is thought to play an important growth regulatory role in tumor development and progression. In this report, we investigate the association of altered cyclin expression with other prognostic indicators (histological grade, lymph node status, estrogen receptor, p53, and c-erbB-2) in the progression of human breast cancer. MATERIALS AND METHODS: Surgical tumor specimens were obtained from 16 breast tubular ductal, and invasive ductal carcinomas and grafted onto gnotobiotic nude (nu/nu) mice. The expression diversity and distribution of the localization of the protein products of the c-erbB-2, cyclins D1 and D3, p53, and estrogen receptor were characterized immunohistochemically and the results in the original tumor (T0) were compared with those in the tumors that developed in nude mice (T1) xenografts. RESULTS: The T0 tumors exhibited a diversity of cellular morphology in the tumor matrix and diversity in expression of these proteins. These specific changes were also preserved in the T1 tumors. Whereas 67% of the T1 tumors exhibited high numbers of estrogen receptorpositive nuclei, only 50% of these tumors grew when grafted onto nude mice. The histological grade (14/15 were G2 to G3) and metastatic malignancy in the lymph nodes (10/15) did not appear to be related to tumor growth in the nude mouse. There was no relationship between those tumors which exhibited high percentages of c-erbB-2- and p53-positive cells and growth in nude mice. A strong association (p < 0.001) was observed between the overexpression of cyclin D1 transcripts in the T0 tumors and the continued growth of the T1 tumors in nude mice. In the T1 tumors, both cyclins D1 and D3, estrogen receptor, and p53 were observed in 49% to 86% of the cells of the T1 tumors examined; the number of cells expressing c-erbB-2 protein varied widely in these tumors. CONCLUSIONS: The results indicate that the tumor matrix exhibits a diversity in the level of phenotypic expression of genes involved in cellular growth of breast tumors in both the T0 or T1 host environment. Changes in cyclin activity appear to correlate with the vigorous level of breast tumor growth and progression.

Adult↗

PubMed1997

Consumer satisfaction: a key to financial success in the managed care environment.

To be successful a company must have the ability to change and be focused on meeting customer needs. The author proposes that health care providers must expand their attention beyond traditional purchasers of services, employers, and insurers and focus on redesigning consumer satisfaction programs and tools to fit the new market environment. Changing from a fee-for-service system to a managed care system means patients are paying an increasing portion of the costs for coverage and care.

Consumer Behavior↗

PubMedDate not supplied

Deciding to make the switch to ambulatory services.

With the health care environment changing so rapidly, this may be a time for nurse executives to consider moving from a traditional nurse executive position with inpatient focus to an ambulatory care or outpatient one. The nurse executive can evaluate her or his skills to determine if ambulatory administration is a good career move. In this article, the author, who has made the switch to ambulatory care, gives insightful advice to nurse executives who may be considering a similar move.

Ambulatory Care↗

PubMed1995

Unusual pathogens for respiratory infections.

There are a large number of unusual pathogens for respiratory tract infections. The list of such pathogens is continuously changing because of changes in our environment, changes in the host (especially immunosuppression), and advances in medical technology, which allow minimally or otherwise nonpathogenic microorganisms to cause respiratory tract infections. Changes may also occur in common microorganisms such as penicillin-resistant pneumococci or multidrug-resistant Mycobacterium tuberculosis. Finally, usual pathogens may result in unusual manifestations.

Community-Acquired Infections↗

PubMedDate not supplied

[Is apoptosis a "programmed cell death"?].

Many authors consider apoptosis as a programmed cell death (PCD). Their opinion is based usually on the dependence of cell death on the protein-opinion and RNA synthesis, on the intranucleosomal fragmentation of DNA and on the expression of genes, which can induce apoptosis. However our analysis of numerous literature data on the apoptotic death (judging by their morphological criteria) of different cell kinds induced by various agents shows: internucleosomal fragmentation of DNA is neither a trigger, nor a reliable proof for apoptotic death; protein- and RNA synthesis, as well as expression of P53 genes is also not a necessary condition for that and is important only in some combinations of the cell type and state and the nature of the damaging agent. Thus, the existence of immanent cell death program requires some more proofs and for present the term PCD may be undoubtedly attributed only to the genetically determined processes intended to remove such cells and organs which become unnecessary for the following development, in short, PCD is a term on the level of organism. We propose that character and sequence of destructive processes at apoptotic cell death are conditioned by the conformational changes in genome as result of the cellular environment changes caused by the action of damaging agents on the cellular membranes.

Animals↗

PubMed1998

Credit analysis of nonprofit continuing care retirement communities.

The continuing care retirement community (CCRC) industry's growth has gained the attention of the financial community. As the industry's financial and regulatory environments change, credit analysts are developing analytical tools to evaluate these changes. The following article discusses some of these tools, provides a sample credit profile of a CCRC, and reviews recent accounting changes that will affect CCRC credit analysis.

Aged↗

PubMed1998

Monovalent cation fluxes and physiological changes of Debaryomyces hansenii grown at high concentrations of KCl and NaCl.

Debaryomyces hansenii showed an increased growth in the presence of either 1 M, KCl or 1 M NaCl and a low acidification of the medium, higher for the cells grown in the presence of NaCl. These cells accumulated high concentrations of the cations, and showed a very fast capacity to exchange either Na+ or K+ for the opposite cation. They showed a rapid uptake of 86Rb+ and 22Na+. 86Rb+ transport was saturable, with K(m) and Vmax values higher for cells grown in 1 M NaCl. 22Na+ uptake showed a diffusion component, also higher for the cells grown with NaCl. Changes depended on growth conditions, and not on further incubation, which changed the internal ion concentration. K+ stimulated proton pumping produced a rapid extrusion of protons, and also a decrease of the membrane potential. Cells grown in 1 M KCl showed a higher fermentation rate, but significantly lower respiratory capacity. ATP levels were higher in cells grown in the presence of NaCl; upon incubation with glucose, those grown in the presence of KCl reached values similar to the ones grown in the presence of NaCl. In both, the addition of KCl produced a transient decrease of the ATP levels. As to ion transport mechanisms, D. hansenii appears to have (a) an ATPase functioning as a proton pump, generating a membrane potential difference which drives K+ through a uniporter; (b) a K+/H+ exchange system; and (c) a rapid cation/cation exchange system. Most interesting is that cells grown in different ionic environments change their studied capacities, which are not dependent on the cation content, but on differences in their genetic expression during growth.

Adenosine Triphosphate↗

PubMed1976

Estimating the risks for offspring of first-cousin matings. An approach.

Effects of parental consanguinity on morbidity and mortality can be estimated from observations on families ascertained through a child with a disease or defect, provided that appropriate corrections are made for the ascertainment bias. The risk of first-cousin parents having a child with a recessively inherited disease appears to be low (less than 1%). Data obtained by this approach suggest that the increased infant mortality associated with inbreeding (upon which calculations of lethal equivalents are based) may result in part from environmental differences between consanguineous and nonconsanguineous matings, which may be changing. Thus estimates of the number of lethal equivalents in a population can change as the environment changes.

Abortion, Spontaneous↗