PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Continuous Evolution”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMed1985

Selective nontreatment of handicapped newborns: a critical essay.

The neonatal intensive care unit is the site of some of the most dramatic technology, complex decision-making and costly activity in the current range of medical institutions. Thus, the decisions made there are particularly visible, and of concern to a society which has increasingly scrutinized and challenged medical practices. Questions of marginal utility and cost-benefit relationships are becoming increasingly prominent. These concerns are heightened by the social and political tensions over issues of the time of initiation of life, quality of life, and assurances of equity for those less well off or handicapped from birth. Robert Weir's book, Selective Nontreatment of Handicapped Newborns, successfully summarizes the current dilemmas and identifies areas of uncertainty and lack of knowledge which cloud the decision-making processes. The book reviews the positions of the major protagonists of the last several years; inevitably, their positions will undergo continuous evolution in response to new data and vigorous political and public policy activity. Weir appropriately identifies the difficulty in arriving at an accurate prognosis as an important and prominent problem in decision-making about defective newborns. The population of surviving, compromised newborns is relatively unfamiliar and their problems remain largely unstudied. Weir's discussion of the desirability of the establishment of Infant Care Review Committees in those institutions which care for defective and handicapped newborns thoughtfully concludes that such committees are, on the balance, desirable. As experience accumulates with Infant Care Review Committees, they should serve the positive purpose of generating open discussion of legitimate disagreements. These committees will provide a forum in which decision-makers can disclose uncertainty, consider alternatives, and receive counsel.(ABSTRACT TRUNCATED AT 250 WORDS)

Persons with Disabilities↗
PubMed1984

Hodgkin's disease.

The outlook for patients with Hodgkin's disease has improved dramatically over the past 20 years. The question is no longer whether cure is possible, but rather, how can cure be best achieved. With better understanding of the biology of Hodgkin's disease and with continued evolution of treatment approaches, the goal of curing all patients with Hodgkin's disease is clearly within reach. This article provides a summary of current concepts in the biology and management of Hodgkin's disease. Staging, treatment options, and complications of therapy are discussed.

Adolescent↗
PubMed1991

From quality assurance to quality management in long term care.

This article describes the continuing evolution of the quality assurance program at Crown Nursing Home, a privately owned, skilled long-term care facility in Brooklyn, New York, into quality management. Activities are intended to improve the systems and processes of resident care, develop and implement practice guidelines, integrate suppliers and vendors into the facility processes, use information systems for indicator monitoring, encourage residents and family participation, provide care through a team approach, and promote human resource management and staff enhancement.

Clinical Protocols↗
PubMed1993

Canine parvovirus.

Canine parvovirus is a truly new pathogen of dogs that emerged in the late 1970s. Initially seen as epidemic disease in all dogs, parvoviral enteritis is now primarily a disease of 1- to 6-month-old dogs. Maternal antibody interference with immunization accounts for the vast majority of vaccine "breaks." Molecular virologic methods have revealed continued evolution of the virus, but this appears to be of greater academic than practical interest. Clinical diagnosis can be definitive in fulminant cases but requires laboratory support--usually demonstration of virus in the feces--in less clear-cut cases. Treatment remains symptomatic, based simply on principles of good supportive care. As the virus is firmly entrenched in both the wild and domestic canine population, elimination of the virus is impossible, and CPV-2 will remain a concern for the small animal practitioner indefinitely.

Animals↗
PubMed1986

The pH dependence of proton-deuterium exchange, hydrogen production and uptake catalyzed by hydrogenases from sulfate-reducing bacteria.

Different patterns have been found in the pH dependence of hydrogenase activity with enzymes purified from different species of Desulfovibrio. With the cytoplasmic hydrogenase from Desulfovibrio baculatus strain 9974, the pH optima in H2 production and uptake were respectively 4.0 and 7.5 with a higher activity in production than in uptake. The highest D2-H+ exchange activity was found also at pH 4.0 but the optima differed for the HD and the H2 components. Both similarly rose when the pH decreased from 9.0 to 4.5, but the rate of H2 evolution slowed whereas the HD evolution continued rising till pH values around 3.0 were reached. The H2 to HD ratio at pH above 4.5 was higher than one. With the periplasmic hydrogenase from Desulfovibrio vulgaris Hildenborough, the highest exchange activity was near pH 5.5, the same value as in hydrogen production. The periplasmic hydrogenase from Desulfovibrio gigas had in contrast the same pH optimum in the exchange (7.5-8.0) as in the H2 uptake. The ratio of H2 to HD was below one for both enzymes. These different patterns may be related to functional and structural differences in the three hydrogenases so far studied, particularly in the composition of their catalytic centers.

Cytoplasm↗
PubMed1992

A randomized controlled trial of early surgery in Duchenne muscular dystrophy.

We performed a randomized controlled trial of early surgical treatment of contractures in 20 boys with Duchenne muscular dystrophy, age 4-6 yr. Surgery consisted of release of hip flexors, removal of iliotibial bands, and lengthening of tendo Achilles bilaterally. All patients were monitored for at least 12 months post-randomization, and assessed quantitatively for muscle strength and function. Surgery corrected the deformities, but had no beneficial effect on strength or function. Indeed, data in the second year showed more rapid deterioration of function in some of the operated boys. There appeared to be continued evolution of pathology following surgery, as assessed by sequential muscle ultrasound and muscle biopsy. We cannot recommend this type of surgery as a routine treatment.

Biopsy↗
PubMed1993

[Characteristics and mechanisms of action of leukocyte depletion filters].

Since their creation, leukocyte depletion filters, used to prepare leukocyte-poor red cell or platelet concentrates, have been continuously evoluting: their volume has been reduced and their composition has been modified, polyester fibers have replaced cotton wool or cellulose acetate. In the same way, their capacity to remove leukocytes has increased. The mechanisms of cell separation are still unclear. Through published studies, different factors seem to be implicated, such as wetable surface of the filter, surface tension or charge density of fibers. It was also observed that removal of lymphocytes from red cell concentrates is rather based on trapping in the fiber network, and that removal of granulocytes, monocytes and platelets is partly due to activation and subsequent adhesion to the fibers. There have been few studies of the mechanism of leukocytes depletion from platelets concentrates.

Adsorption↗
PubMed1995

Orthoses and prostheses.

Orthoses and prostheses include a wide range of devices and strategies for correcting and alleviating dysfunction and disability. Features in these areas of technology include continuing evolution of new devices, further development of well-established approaches, a need for critical assessment, requirements for support from technical and health care workers, and the need to identify funding to achieve efficient programs.

Persons with Disabilities↗
PubMed1994

Geminate recombination of diatomic ligands CO, O2, and NO with myoglobin.

The kinetics of geminate recombination of horse heart myoglobin with the diatomic ligands carbon monoxide, dioxygen, and nitric oxide have been reexamined. The new measurements are distinguished from previous studies by (1) consideration of the complete time range longer than 1 ps, (2) inclusion of the effect of temperature changes near ambient, (3) attention to the relation between recombination kinetics and the yield of dissociated partners on the millisecond time scale, and (4) use of singular value decomposition in the analysis. These picosecond results, together with earlier nanosecond data, for O2 prove that models incorporating one, two, or even three discrete intermediates are not sufficient to account for all features of geminate recombination kinetics. Instead, a continuous evolution of the geminate pair distribution is preferred.

Animals↗
PubMed1994

Laparoscopically implantable nerve-stimulating electrode (LINSE): application to the cavernous nerve in acute and chronic canine models.

Using a new laparoscopic procedure, we investigated stimulation of the cavernous nerves to achieve erection in a canine model. The technique was developed during acute experiments in four dogs, following which, chronic studies (4- to 6-weeks survival after surgery) were undertaken in three dogs. A monopolar cuff electrode was inserted laparoscopically by a transperitoneal approach and placed around the cavernous nerve. The leads were brought out to the subcutaneous space, where they were attached to stimulation receivers that could be activated by an external radiofrequency transmitter. An intracavernous pressure elevation indicative of successful stimulation was obtained acutely in five of eight cavernous nerves in the four acute-study dogs and in four of six nerves in the three chronic-study dogs. The implanted equipment associated with four of six cavernous nerves failed mechanically in the chronic-study animals, such that only two receiver-electrode sites were intact at the time of sacrifice 4 to 6 weeks later. Transmitter-driven stimulation of one of these two sets produced an intracavernous pressure rise above 100 cm H2O. We present this technique as part of the continuing evolution of laparoscopy as both a research and a clinical tool. The present use of the laparoscopically implantable nerve-stimulating electrode is a new animal research tool and a potential first step in the human application of the technology.

Animals↗
PubMed1993

Prevalence of the type I and type II DHFR genes in trimethoprim-resistant urinary isolates of Escherichia coli from Greece.

Trimethoprim resistance in 64 Escherichia coli urinary isolates from five hospitals in Greece was studied. Of the 40 isolates exhibiting transferable high-level resistance (MIC > 1024 mg/L), 21 hybridized with a specific probe for dihydrofolate reductase (DHFR) I, 13 with a probe for DHFR II, and one with a probe for DHFR V. Eleven isolates hybridized with a probe for transposon Tn7. Among the 17 isolates with non-transferable high-level resistance, seven hybridized with the probe for DHFR I, three with the probe for DHFR II, and eight were Tn7-positive. None of the seven isolates with low-level resistance (MIC 4-1024 mg/L) reacted with the probes used. Of the 28 isolates positive for DHFR I, 12 (43%) failed to hybridize with the Tn7 probe. Conversely, three isolates hybridized with the Tn7 probe, but not with the probe for DHFR I. Colony hybridization experiments showed that all but three transconjugants reacted similarly to their respective parent strains. The plasmids coding for trimethoprim-resistant DHFRs were found to differ on the basis of restriction enzyme analysis. These findings suggest that trimethoprim resistance among E. coli urinary isolates in Greece is mediated predominantly by heterogeneous transferable plasmids encoding either DHFR I or DHFR II. The dissociation between DHFR I and Tn7, together with the high incidence of trimethoprim-resistant isolates which did not hybridize with the probes for the common DHFR I or II types, indicates the continued evolution of trimethoprim resistance determinants.

Bacteriuria↗
PubMed1987

Combined therapy as an alternative to exenteration for locally advanced vulvovaginal cancer. II. Results, complications, and dosimetric and surgical considerations.

We have introduced a therapeutic alternative to exenteration for locally advanced vulvovaginal cancer using surgery for the vulvar (external genital) phase of this disease presentation, combined with radiotherapy for the internal genital phase (with adequate overlap of fields to protect surgical margins). The rationale is that this approach treats the cancer and its dual regional spread patterns, while at the same time preserving the bladder and/or rectum, and should be associated with less morbidity and mortality than exenterative surgery. This report updates our experience with a total of 48 treated cases (37 primary cases and 11 cases of recurrent disease). Of the 37 primary cases, 20 were FIGO stage III, 4 were FIGO stage IV, and 3 other cases represented "field" cancers involving vulva and/or cervix and/or vagina. Utilizing a Life Table analysis, the 5-year survival for the primary cases was 75.6%. Published FIGO survival for stage III is 32% and for stage IV 10.5%. Life Table analysis projects a 62.6% survival for recurrent cases and an overall 72% 5-year survival for all 48 cases treated. With 48 patients treated, 48 bladders and 48 rectums were at risk for surgical removal had exenteration been employed. One patient had a total pelvic exenteration for local failure, and one had a posterior exenteration for local failure. One bladder and one rectum were lost to permanent diversion because of radiation injury. Thus, 5 of these major viscera were lost of the 96 total, and 91 (94.8%) were retained. Radiation therapy and surgical details have been reviewed relevant to local control and local failure and complications. The continuing evolution of treatment modifications of all modalities will be discussed. The apparent advantages of this combined therapeutic approach over exenterative surgery include high probability of bladder and/or rectal preservation, low primary mortality, low treatment morbidity, and very good results in cancer control.

Brachytherapy↗
PubMed1981

Medical technology and academic medicine: the doctor-producers' dilemma.

Diagnostic technologies differ from therapeutic technologies in several ways. Use of a diagnostic technologies is increasing faster than overall medical care. New diagnostic technologies tend to be additive and often have multiple uses. In evaluating their benefits, one should assess marginal, not absolute, utilities and measure clinical as well as financial costs. Although the use of therapeutic technologies is more circumscribed, these technologies tend to be in continuous evolution, especially when new. Comparative evaluations of therapeutic technologies are expensive and time-consuming. Pro-technology reimbursement biases may be the most important of the many factors promoting technology use. Academic medical centers, which have become increasingly clinically specialized, must now compete with their own graduates for specialty patients. At the same time they are urged to respond to contradictory national health policies that favor production of more generalists under a pro-specialty reimbursement system. Suggestions for more appropriate technology use should cover multiple approaches, including the changing of current financial incentives and the use of technology assessment to improve quality of care and education.

Academic Medical Centers↗
PubMed1988

Red cell size heterogeneity during ontogeny.

To determine the manner in which erythrocyte changes occur during ontogeny, several red cell parameters were analyzed in fetuses, newborn infants, children, and adults. Although mean cell volume (MCV) and hemoglobin F (HbF) levels decreased as expected during in utero development, the coefficient of variation of red cell size (%CV), or red cell distribution width (RDW), increased from fetuses to newborn infants. In normal adults, the %CV was 15 (RDW was 13). The %CV in fetuses at 18-24 weeks gestation was 18, and it was 21 at term birth. High values for %CV or RDW indicate significant anisocytosis. Erythropoiesis at the time of birth is not a steady-state condition. Erythrocytes of a wide variety of sizes are present, with the appearance of new small cells on a background of older, larger red cells. This increased anisocytosis suggests that these new erythrocytes do not appear to be due to a smooth, continuous evolution of red cell size, but rather to discrete, perhaps clonal, changes.

Adolescent↗
PubMed1989

The therapeutic community: exploring the boundaries.

The past 20 years have demonstrated the effectiveness of therapeutic community (TC) treatment for drug abuse as it evolved in the United States. We now better understand the influence that psychodynamic features of TC treatment have on character disorder. Best perceived as a setting designed--as society is not--to encourage and support social learning, the TC has succeeded in modifying its programs and adapting self-help methods to serve drug abusers of all kinds and abusers of all drugs. Continued evolution of the TC depends upon development of its already-demonstrated capacity to affect disordered behaviour other than drug abuse. The growth of disordered populations in the United States and increasingly in Great Britain gives urgency to such future employment. Therapeutic communities and TC-like programs for non-drug abusers already exist. But widespread use depends upon strengthening the theoretical underpinnings of TC treatment and establishing closer working relationships between TC's and mainstream medical, mental health and social service institutions.

Humans↗
PubMed1993

Delayed success following radiofrequency catheter ablation.

Two patients who underwent attempted radiofrequency catheter ablation of an atrioventricular accessory pathway experienced delayed abolition of pathway conduction. During the procedures there was transient block in the accessory pathway following multiple ablation attempts at closely spaced sites. Both patients showed evidence of preexcitation at the conclusion of the ablation session but neither showed evidence of accessory pathway conduction during a second electrophysiological study. These observations demonstrate that in patients in whom transient block of the accessory pathway is produced, continued evolution of radiofrequency energy lesions may result in the eventual success of an initially unsuccessful ablation session.

Adenosine↗
PubMed1978

Behavioral marriage therapy. III. The contents of Gurman et al. may be hazardous to our health.

This paper was written as a reply to a critique of behavioral marital therapy (BMT) by Gurman, Kniskern, and Knudson (6, 7). The reply is divided into four sections. First, the paper addresses the critics' comments on the conceptual model put forth by BMT, correcting and clarifying various misconceptions, and restating some of the basic ideological principles in the behavioral model. Second, the paper discusses behavioral change techniques and technology, along with extratechnological treatment considerations. Again, misrepresentations of BMT are corrected. Third, an analysis of the literature investigating the therapeutic efficacy of BMT is reviewed, and the conclusion is reached that BMT is demonstrably effective, at least for a substantial number of mildly to moderately distressed couples. Criticisms are made of the analysis of the same literature conducted by Gurman et al. We conclude that, contrary to the spirit of the paper by Gurman et al., BMT is a viable framework for conceptualizing and treating relationship problems and that the commitment of its adherents to experimental investigation promises continued evolution, refinement, and improvement.

Behavior Therapy↗