Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “transition”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 127 records · Page 7Linked to original sources
PubMed1988

Opaque-white phenotype transition: a programmed morphological transition in Candida albicans.

This paper reports that the opaque and white phenotypes of Candida albicans constitute a true high-frequency reversible transition system. The rDNA restriction fragment and orthogonal field alternating gel electrophoresis profiles of opaque and white phenotypes are indistinguishable, and a genetic marker introduced into a white strain is present in all opaque derivatives of this strain. Opaque and white derivatives appear markedly different on a bismuth indicator medium and differ in a number of other respects. We have used bismuth medium to examine the spontaneous and temperature-induced frequencies of transition from opaque to white. The temperature-induced transition from opaque to white does not occur when opaque cells are held in water.

Candida albicans↗
PubMed2003

The transition from adolescence to adult life: physiology of the 'transition' phase and its evolutionary basis.

The human life span is comprised of several life phases, each characterized by its own physiology. These phases (pre-natal, neonatal, infancy, childhood, juvenile, puberty, adolescence, prime and senescence) are important for the development of many biological and psychological processes. The 'transition' from adolescence to adult life in the human is a lengthy process in comparison with other species, and its evolutionary development has been long and complex. In this article, the characteristic features of this transition will be discussed, as well as the theory that the transition from adolescence to adult life should be considered as a life phase in its own right.

Adolescent↗
PubMed2005

Transfer versus transition: success in pediatric transplantation brings the welcome challenge of transition.

CONTEXT: Increasing success with solid organ transplantation in children has increased the numbers of adolescents and young adults who are at an age to transfer to adult healthcare. OBJECTIVE: To determine the nature of transfer/transition of adolescents and young adults to adult healthcare. DESIGN: Using a qualitative approach, 24 young adults provided answers to 12 questions about their transfer to adult healthcare. Responses were compared to identify themes. SETTING: Subjects had been pediatric patients at Children's Hospital of Pittsburgh. Most were transferred to the University of Pittsburgh Medical Center. PATIENTS: The subjects had received, or were on the list to receive, solid organ transplants and had been transferred within 18 months of the study. RESULTS: Twenty-four of 37 potential subjects completed interviews. Those who participated were enthusiastic about making a contribution to the transfer process. Most subjects cited difficulty leaving the pediatric system. Challenges included abrupt transfers, insufficient communication between pediatric and adult specialty providers, and becoming "lost to follow-up." However, there was a consistent, clear statement that subjects preferred being treated as adults. They liked healthcare staff addressing them instead of their parents, being spoken to in an adult manner, and being responsible for their own care. Suggestions for improvement included early introduction of the concept of transition to adult care, providing written material about the transition process, and use of pediatric/adult social work collaboration to provide support for young adults in transition.

Adaptation, Psychological↗
PubMed1990

Families in supportive care--Part I: The transition of fading away: the nature of the transition.

The entire family unit is affected when one of its members is in need of supportive care; however, relatively few studies pertaining to palliative care have focused on the family as a unit. The purpose of this study was to examine the experience of families having a member with advanced cancer who was receiving palliative care either at home or in the hospital. Eight families (24 family members) participated in semistructured interviews which were audiotaped, transcribed, and subjected to qualitative methods of analysis. Results indicated that the families' experience can be conceptualized as a transition of fading away. The transition began with an ending, characterized by the processes of redefining and dealing with burden. A period of chaos, confusion, fear, and uncertainty characterized the neutral zone. The end point of the transition was a new beginning where families focused on living day-to-day and preparing for death.

Adaptation, Psychological↗
PubMed1990

[Mean transit time and partial mean transit time of spirogram in 628 normal adolescents].

The mean transit time(MTT) and partial mean transit time(MTTp) were measured and analysed by "direct method" in 628 cases of normal adolescents in Cheng-du. The results showed that both MTT and MTTp were increased with age and prolonged with the decay of lung volume. Besides, the FVC-t curve was not single exponential in nature. The specific mean transit time (SMTT) was introduced by correcting MTT with 0.5 FVC and represented the MTT when unit volume of gas passed through just at that lung volume. SMTT was highly negatively correlated with age. This reflected the development and growth of the lung recoil and airway conductance in adolescents.

Adolescent↗
PubMed1986

Head-up/head-down transition: measurement of transition times.

A method was developed to measure transition times between a head-up signal and a response given to a head-down display. Various arrangements of motor response (vocal, hand) and HDD images were used. In the first experiment, vocal and manual response times were recorded in a current fighter aircraft mock-up situation. The shortest times were obtained for voice responses. The time elapsed between a HUD signal and the simple response to the HDD was approximately 1600 ms. The time for physical transition where accommodation changes occur was 700 ms. In the second experiment, two types of images were displayed on the HDD: a "positive" contrast (green symbol on black background), and a "negative" contrast (black symbol on green background) in order to compare accommodation to structured and unstructured backgrounds. Perception time was significantly shorter for the "positive" contrast, and transition times were similar to those measured in the first experiment. This method permits the evaluation in a dynamic aeronautical environment of the acquisition and processing of information. Changes in psychological conditions (heavier information processing) and/or physiological conditions (changing accommodation, gaze axis, convergence) can be evaluated in future research.

Accommodation, Ocular↗
PubMed1980

Transitional objects in transition.

Winnicott's original definition of a transitional object was that it is inanimate, is endowed by the infant with special properties and is of value in the developmental task of acknowledging that Mother (or her breast) is alive, is not a physical part of the baby, nor yet its external possession. I have tried in this short paper to show how a disservice has been done to Winnicott's original perception of the significance of transitional objects, by broadening the concept of transitional phenomena too far in a way which actually diminishes their value in understanding the growth of the mind. Further study and discussion is needed of the complex role of the baby's suck-rag, elucidation of which will be furthered by adherence to a more specific definition. Clinical material is present to illustrate this claim.

Anxiety↗
PubMed1983

Transitional cell carcinoma of bladder originating from transitional cell carcinoma of anus.

A unique case of transitional cell carcinoma of the bladder with the primary being in the anus is reported. The patient presented with acute urinary retention from a large bladder tumor, which was thought to be primary to the bladder. Biopsy of the bladder revealed transitional cell carcinoma, microscopically indistinguishable from the primary cloacogenic carcinoma diagnosed seven years previously.

Aged↗
PubMed2004

Expression of the tumor suppressor protein 14-3-3 sigma is down-regulated in invasive transitional cell carcinomas of the urinary bladder undergoing epithelial-to-mesenchymal transition.

The 14-3-3 proteins constitute a family of abundant, highly conserved and broadly expressed acidic polypeptides that are involved in the regulation of various cellular processes such as cell-cycle progression, cell growth, differentiation, and apoptosis. One member of this family, the 14-3-3 isoform sigma, is expressed only in epithelial cells and is frequently down-regulated in a variety of human cancers. To determine the prevalence of 14-3-3 sigma silencing in bladder cancer progression, we have studied the expression of this protein in normal urothelium and bladder transitional cell carcinomas (TCCs) of various grades and stages using two-dimensional gel electrophoresis in combination with Western blotting and immunohistochemistry. We show that the expression of 14-3-3 sigma is down-regulated in invasive TCCs, particularly in lesions that are undergoing epithelial-to-mesenchymal conversion. Altered expression of 14-3-3 sigma in invasive TCCs is not due to increased externalization of the protein nor to an aberrant proliferative potential of neoplastic cells. Furthermore, we found that impaired 14-3-3 sigma expression is not associated with increased levels of the dominant-negative transcriptional regulator Delta Np63. Down-regulation of 14-3-3 sigma was confirmed by indirect immunofluorescence using a peptide-based rabbit polyclonal antibody specific for this protein. We also show that the expression of 14-3-3 sigma is highly up-regulated in pure squamous cell carcinomas. Taken together, these results provide evidence that deregulation of 14-3-3 sigma may play a key role in bladder cancer progression, in particular in differentiation events leading to epithelial-to-mesenchymal transition and stratified squamous metaplasia.

14-3-3 Proteins↗
PubMed2005

Mechanism of thermal phase transition of a ferroelectric liquid crystal with monotropic transition temperature studied by infrared spectroscopy combined with principal component analysis and sample-sample two-dimensional correlation spectroscopy.

Infrared (IR) spectra of FLC-154 (FLC: ferroelectric liquid crystal) with monotropic phase transition under a nonalignment state with a sample layer thickness of 24.5 microm were measured for heating process from 55 to 90 degrees C and a cooling process from 90 to 55 degrees C in increments of 1 degrees C. The thermal dynamics of FLC-154 were investigated by use of IR spectroscopy combined with principal component analysis (PCA) and sample-sample two-dimensional (2D) correlation spectroscopy. During the cooling, the FLC-154 molecule passes through the monotropic smectic-C* (Sm-C*) phase, which is transformed from the Sm-A phase. The results from PCA suggest that during the heating process, the thermal dynamics of the alkyl chains, core moiety, and C=O groups are similar to each other. Furthermore, PCA and sample-sample 2D correlation spectroscopy indicate that the alkyl chains and C=O groups in the chiral and core moieties are responsible for the emergence of the Sm-C* phase. This conclusion is very important because the IR data have given more evident cause for the emergence of the Sm-C* phase than the theoretical models such as the molecular-statistical theory of ferroelectric ordering and the indigenous polarization theory. Moreover, it has been found that some of the trans conformations of the alkyl chains of FLC-154 change partly to the gauche conformation when the phase transition from the crystalline phase to the Sm-A phase occurs. It has also been found that the intermolecular interactions of the C=O group in the core moiety in the Sm-A phase are weaker than those in the crystalline phase and that the conformational change occurs on the C-O-C bonds in the core moiety upon going from the crystalline to the Sm-A phase.

Algorithms↗
PubMed1980

Adolescents in transition: a look at a transitional treatment center.

This article describes the structure, philosophy, and goals of a high expectations halfway house program for adolescents. The Transitional Treatment Center (TTC) is a residential treatment program for emotionally disturbed adolescents making the transition from institutionalization to independent community life. Topics covered are specification of the TTC program objectives, methods for monitoring residents' progress towards resocialization and plans for future programming.

Adolescent↗
PubMed1998

Impact of Bulk Phase Transitions and Wetting Transitions on Adsorption Isotherms in Binary Systems in Contact with Solid.

This paper presents several studies essentially on the solid/liquid interface. The studied system is the liquid binary mixture water-2,5dimethylpyridine (2,5DMP) in contact with an amorphous silica (Aerosil type). The study of wetting along the two-liquid bulk phases coexistence in contact with silica allows the determination of a wetting transition temperature, which is an important parameter for the adsorption behavior at coexistence. The adsorption isotherms in a diluted phase and in a concentrated phase present some very significant features. In diluted solutions the isotherms show a succession of plateaus; these transitions of layers persist in concentrated phases presenting a sequence of maxima and minima of relative adsorption (Gibbs adsorption) of 2,5DMP with respect to water. In concentrated solutions, they interfere with the prewetting that gives an original shape to the isotherms in concentrated solutions. These adsorption measurements were completed by activity measurements which allow one to obtain the chemical potential of mixtures and linked information. The whole study shows the behavior of colloidal suspensions close to bulk phase changes. Copyright 1998 Academic Press.

Journal Article↗
PubMed2007

Correlation between the total volume, transitional zone volume of the prostate, transitional prostate zone index and lower urinary tract symptoms (LUTS).

OBJECTIVES: Currently available studies show controversial data between the symptoms of the lower urinary tract and the volume of the prostate gland. The objective of the present study is to evaluate the relationship between the score of the lower urinary tract symptoms assessed according to the International Prostate Symptoms Score (IPSS) and the total (TV) and transitional (TZV) zone volume of the prostate and transitional prostate zone index (TZI). MATERIALS AND METHODS: From 223 men with a mean age of 59.3 years (varying from 50 to 75), the scores of lower urinary tract symptoms, measured by the IPSS and TV and TZV, determined by transrectal ultrasonographies, were obtained. Furthermore, the TZI was determined in all cases by the TZV to TV rate of the prostate. The relationship between TV, TZV, and TZI and the data obtained using the symptoms score was statistically determined. RESULTS: The TV of the prostate were 25.5 +/- 10.3, 25.0 +/- 9.3, and 28.9 +/- 13.5 g in individuals with mild, moderate, and severe symptoms, respectively (P = 0.15). Similarly, there was no significant difference when the TZV (7.6 +/- 6.3, 7.6 +/- 5.8, and 9.6 +/- 6.8 g, respectively; P = 0.22) and the TZI (0.26 +/- 0.1, 0.27 +/- 0.1, and 0.30 +/- 0.1, respectively; P = 0.33) were compared in the groups of men with mild, moderate, and severe symptoms of urinary difficulty. However, the quality of life (QoL) scores presented progressively worse values (1.7 +/- 1.3, 3.1 +/- 1.4, and 4.4 +/- 1.2) as the severity of the lower urinary tract symptoms became worse (P < 0.001). The Pearson correlation coefficient between the TV (r = 0.15; P = 0.02), TZV (r = 0.16; P = 0.02), and the TZI (r = 0.14; P = 0.03) with the prostate symptom scores showed low values although they were positive and statistically significant. The highest correlation was observed when the QoL related to urinary symptoms and symptom scores (r = 0.61; P < 0.001) was analyzed. CONCLUSIONS: A low correlation was found between the score lower urinary tract symptoms assessed by IPSS and the different volumes of the prostate gland (TV, TZV) and prostate TZI, and, on the other hand, an inverse correlation between the intensity of urinary symptoms and QoL, supporting the idea of multifactorial aspects related to the genesis of urinary symptoms in men.

Aged↗
PubMed1981

Phase transitions and cholesterol effects in phospholipid liposomes. A new method employing the enhancement of the O-O vibronic transition of pyrene.

The enhancement of the weakly allowed 0-0 vibronic transition in the fluorescence spectrum of the probe pyrene, which we previously showed to result from ground-state complexation with polar groups, has been shown in the present study to offer a new method for determining phase transition temperatures of liposomes and for studying the effects of cholesterol on the structure of their semipolar glycerol backbone. For dipalmitoylphosphatidylcholine it is found that small cholesterol contents (approximately 9 mol%) induce an increase in the polarity of the microenvironment of the probe, whereas contents greater than or equal to 13 mol% induce a decrease in the polarity. The results are discussed in terms of cholesterol effects on the frequency and extent of thermally-induced structural fluctuations which, in turn, affect the penetration of the probe into the bilayer.

Chemical Phenomena↗
PubMed1983

The influence of water on the phase transition of sheep lung surfactant. A possible mechanism for surfactant phase transitions in vivo.

The effect of water on the thermal properties of sheep lung surfactant lipids was determined by differential scanning calorimetry. Dry surfactant exhibited a phase transition with an upper limit of about 54 degrees C, whereas that of the fully hydrated surfactant was about 30 degrees C. The effect of water was confined to a range of hydration values from 0 to 25%. The results indicate that pulmonary surfactant lipids are capable of undergoing both thermotropic and lyotropic mesomorphism in vitro. The degree of hydration of the surfactant could influence its in vivo biophysical role in alveolar dynamics. Indeed, small changes in the surfactant to water ratio induced by regional differences in the surfactant concentration at the alveolar surface during alveolar expansion and contraction could be sufficient to trigger isothermal phase transitions in the surfactant lipids. This would allow changes to occur in the equilibrium between solidus and fluidus surfactant during the respiratory cycle.

Animals↗
PubMed1985

A modified method for the simultaneous determination of regional single-transit brain extraction of diffusion-limited compounds and cerebral blood flow: utilization of non-invasive measurement of transit time.

A dual-label radioisotope method to measure regional cerebral blood flow (CBF) with [14C]butanol and the single-transit brain extraction of [3H]water (Ew) was modified to permit concomittant measurement of the exit time through the cerebrovasculature of a bolus (BET) of 51chromium (51Cr)-labeled ethylenediaminetetraacetic acid (EDTA) in rodents. First, [51Cr]EDTA was injected intravenously via the femoral vein and its transit through cerebrovasculature determined by external gamma counting. The BET measurement was then used to determine the optimum time for animal sacrifice for subsequent measurement of CBF and Ew to minimize both intravascular contamination and washout of butanol and water. This procedure resulted in higher CBF at moderate hypercapnia and slightly lower Ew as a function of arterial CO2 content than previously found using a fixed interval for sacrifice.

1-Butanol↗
PubMed1998

Complexes between porin, hexokinase, mitochondrial creatine kinase and adenylate translocator display properties of the permeability transition pore. Implication for regulation of permeability transition by the kinases.

Complexes between hexokinase, outer membrane porin, and the adenylate translocator (ANT) were recently found to establish properties of the mitochondrial permeability transition pore in a reconstituted system. The complex was extracted by 0.5% Triton X-100 from rat brain membranes and separated by anion exchanger chromatography. The molecular weight was approximately 400 kDa suggesting tetramers of hexokinase (monomer 100kDa). By the same method a porin, creatine kinase octamer, ANT complex was isolated and reconstituted in liposomes. Vesicles containing the reconstituted complexes both retained ATP that could be used by either kinase to phosphorylate external creatine or glucose. Atractyloside inhibited this activity indicating that the ANT was involved in this process and was functionally reconstituted. Exclusively from the hexokinase complex containing liposome internal malate or ATP was released by addition of Ca2+ in a N-methylVal-4-cyclosporin sensitive way, suggesting that the hexokinase porin ANT complex might include the permeability transition pore (PTP). The Ca2+ dependent opening of the PTP-like structure was inhibited by ADP (apparent I(50), 8 microM) and ATP (apparent I(50), 84 microM). Also glucose inhibited the PTP-like activity, while glucose-6-phosphate abolished this effect. Although porin and ANT were functionally active in vesicles containing the creatine kinase octamer complex, Ca2+ did not induce a release of internal substrates. However, after dissociation of the creatine kinase octamer, the complex exhibited PTP-like properties and the vesicles liberated internal metabolites upon addition of Ca2+. The latter process was also inhibited by N-methylVal-4-cyclosporin. The activity of peptidyl-prolyl-cis-trans-isomerase (representing cyclophilin) was followed during complex isolation. Cyp D was co-purified with the hexokinase complex, while it was absent in the creatine kinase complex. The inhibitory effect of N-methylVal-4-cyclosporin on the creatine kinase complex may be explained by direct interaction with the creatine kinase dimer that appeared to support octamer formation.

Adenosine Diphosphate↗
PubMed1997

The photosynthetic oxygen evolving complex requires chloride for its redox state S2-->S3 and S3-->S0 transitions but not for S0-->S1 or S1-->S2 transitions.

The Cl- requirement in the redox cycle of the oxygen-evolving complex (OEC) was determined by measurements of flash-induced UV absorbance changes in Cl(-)-depleted and Cl(-)-reconstituted photosystem II membranes. On the first flash after dark adaptation the spectrum and amplitude of those changes, known to reflect the oxidation of MnIII to MnIV on the S1-->S2 transition, were the same in the presence or absence of Cl-. On the second and later flashes, however, absorbance changes in Cl(-)-depleted samples revealed only electron transfer from tyrosine to quinone which reversed slowly in the dark by charge recombination and did not produce the S3-state. A rapid method was developed to remove Cl- after producing the S3-state by two flashes. The lifetime of the S3-state was found to be unaffected by Cl(-)-depletion, in contrast to the 20-fold stabilization of the S2 lifetime by Cl- removal, and the Cl(-)-depleted S3-state did not proceed to S0 on flash illumination. However, when the same Cl(-)-depletion procedure was applied after producing the S0-state by three flashes, further advance to S2 by two additional flashes was not impaired by the absence of Cl-. The requirement for Cl- only on the S2-->S3 and S3-->S0 transitions can be rationalized by the hypothesis that Cl- is required for electron transfer between manganese ions within the oxygen-evolving complex.

Chlorides↗